I'm a bit drunk but what significance does 3 BTC have here?

If you mine solo and find a block doesn't it still pay 25 BTC plus transactions?  If you mine in a pool then isn't what matters your rate of finding shares/hour?  I can't think of any reason why 3 BTC is relevant to anything - it's 100 GH/S mining for Y*X time or 1 GH/S mining for 100*Y*X time : it's exixtence says nothing about what X or Y is.