When I wrote about the Edinburgh Fringe bubble bursting the other day I mentioned that I'd reviewed Daniel Kitson in London for the Evening Standard recently even though he didn't invite reviewers. Perpetually grumpy stand-up Andre Vincent responded via Twitter to ask me why I gave precious review space to a comedian who didn't want to be reviewed when I could have given it to countless comedians who would appreciate some coverage.

This raises a question about the purpose of critics which is particularly apposite at the moment. Last week I heard that the Independent on Sunday plans to axe its entire arts reviewing staff in September. The paper says it will still be covering the arts, but this act has sent shudders through the reviewing community. American newspapers have also cut back on critics recently and with newspapers squeezed more than ever there may be more cuts to come.

So, why should we have reviewers in general and comedy reviewers in particular? Firstly to answer Andre's question. If The Standard had not commissioned me to review Daniel Kitson they would not have commissioned a different comedy review from me. That's not how newspaper space is allocated. They would probably have commissioned the next most important arts event which could have been opera, classical music, anything else really before they ask me to review an open spot at the Chucklebucket Club.

But Vincent also asks whey I reviewed someone who didn't want to be reviewed. I guess there are a million reasons to review Daniel Kitson and only one not to – that he doesn't want critics in. Vincent might argue that I should respect that. I disagree. The main reason for paying for a ticket to write about him is that he is generally regarded as the most talented stand-up of his generation. Every new work he produces is interesting and newsworthy and, particularly with Kitson, who does not crop up on television and barely on the internet, this is a way for people to get some kind of flavour, however diluted, of what he is currently up to. I wouldn't buy a ticket for anyone else. Incidentally, this was not a preview or warm-up, this was a finished show. I don't review his try-outs because I think that's wrong, but The Telegraph actually reviewed his early warm-up at Latitude for his next theatre show – that's how important Kitson is. I have already removed one piece on Kitson here about his low-key late night Resonance FM show when requested, but his Battersea Arts Centre show last month was a finished show for public consumption with punters paying for tickets, not just tuning in.

Another reason for reviewing Kitson, then, is as a guide for consumers. Some people have drifted away from him after his early breakthrough because he has done more theatrical shows recently. This set was more of a move back towards stand-up so it was useful to review him to give people an idea of what he is up to now so that they can decide whether to buy tickets – if there are any left – to see him this time. And I should emphasise if I haven't already, that Kitson's reticence is an exception in the industry. Publicists and venues like reviewers because by and large they help to shift tickets.

And I suspect that even comedians who claim they do not read their reviews rather like being written about, as long as something nice is being said. Reviews clearly matter to them. Plenty have quoted lines – good and bad – from my reviews back to me over the years. And performers who pay attention are quite right not to be so resistant. Some critics do know a bit about what they are talking about – maybe performers should look on reviews as extra free directorial notes.

So proper professional, decently paid critics rather than citizen bloggers do serve an essential purpose. And re Kitson, there is also an old reporters' adage that the stories that you should write about are the ones that the subjects don't want written. But there are other reasons for comedy criticism. I'm up in Edinburgh at the moment during the one month of the year when comedy is consistently taken seriously as an art form. Criticism is part of the ongoing conversation about comedy. It is not just about passing thumbs-up judgements like Nero or making smartarse put-downs like some sub-Charlie Brooker. It is about looking at trends and developments in the art form.

Comedy criticism is not just about assessing who is good, otherwise we could just tweet star ratings and not bother writing reviews. Short punchy newspaper write-ups have their place but what I like about Beyond The Joke is that there is no word count. Space on the web is, as far as I know, infinite. If I want to write a thousand words on James Acaster I can. Where would I get the chance to do that in a newspaper nowadays?

Yes, of course critics can be written off as parasites. Of course they would not exist if there were not hard-working, creative artists out there producing art for us to write about. but that certainly does not mean that we are worthless. Far from it. Judging by the number of emails I'm getting from comedians asking me to review their Fringe shows it feels as if the relationship is more mutual, like those birds that live on the backs of hippopotami and eat the insects that bother the hippos.

Daniel Kitson might not want critics to circle around him, but there are plenty of comedians who do. Nobody likes to be ignored and even a bad review is an acknowledgement of your existence. I think that one way or another, whatever happens to newspapers in the next decade, comedy criticism is here to stay. Now, on the other hand, if Andre Vincent had been bitching about PRs I might have seen eye-to-eye with him for a change...