It's because the site is free - if anyone could sign up and immediately send messages to everyone else on here, it'd become an impenetrable swamp of spam and trolling within about two minutes; when I first joined, I thought it was stupid too, but so far the points system seems to work.

It takes no time at all to move up through the first few levels and thus be able to chat to anyone you like. Most users aren't bothered about amassing points and the dating has become secondary; many of us are just here for the conversation.