True, although by the time you've signed up and proven ID, you've lost the 'spontaneous' appeal of the site (making it quick and easy to have a bet). I guess the site still has the advantage of low-cost money transfers and no risk of chargebacks, so bitcoins may have a use here.

I wonder if it is possible to use bitcoins and comply with the UK gambling restrictions against money laundering? At first glance, it looks impossible, bitcoins being (supposedly) untraceable. However, you might be able to comply if you insist that winnings are always paid back to the same bitcoin wallet that they came from. The justification here being that your website won't have 'washed' the money any further than it was already laundered.