It's one of those things where it's not essential but you feel obliged because everyone else has one. It's just another form of marketing and God help you if that's all you do to get work.
Having said that it's a bit like having your van signed, it's relatively cheap if you go to the right place and it doesn't cost an arm and a leg to maintain. So even a few jobs a year make it well worth while.
Unfortunately I no lots of people, not just CC who have a very glossy expensive website, but no one ever finds it. Speaking to someone today they got a nice bill from Getty images for £1600 because their crap webdesigner put a royalty stock image on his site and he's liable - not the webdesigner.

Be careful who you choose, get recommendations.