Used to be namecheap required 6 confirmations which was kind of a frustration when you wanted to buy a domain, as you'd have to deposit bitcoins, come back an hour or so later to pay.
Yeah, that was super annoying that you had to
come back to manually finish the process. And their website was really bad at explaining what was going on (you'd deposit BTC and they'd send you back to this page that said "your balance is zero").
But it appears they now process 0 confirmation payments, so you can deposit bitcoins and checkout right away.
Well, that's a bit misleading. Newly-registered domain names aren't functional in less than 60 minutes, so they aren't really accepting "0 confirmation payments". I hate to be picky here but I'm only pointing this out because accepting 0-confirmation payments is always stupid, regardless of which hack-of-the-month has been discovered to make gaming them easier. It would be wrong for people to go around saying "0-confirmation payments are fine because namecheap allows them!"… by the time you have your domain name they'd know if you'd double-spent.