Different people like different styles of chess. The C-Z and C-K [the two colle systems] don't put "pressure" on Black immediately, but that doesn't make them worse. The C-Z aims to contain and constrict Black, the C-K aims to execute a general opening strategy that Black has trouble stopping.
The idea that an opening has to "pressure" your opponent to be good seems a bit over-simplistic. White has historically done just as well with 1.Nf3 as he has with either 1.d4 or 1.e4, but it is hardly a pressuring move. The English opening [1.c4 e5 2.Nc3] puts no pressure on Black at all, yet it is considered totally viable.
I guest wrote a column for chessvibes on what I am certain is the future of the c3-Colle: The Phoenix Attack.