tscCHERRYIt's something different though. TF2Center and TF2Pickup.
They may be different, but ultimately the point is to not reinvent the wheel as far as infrastructure goes. If the major difference between PUGs and lobbies is the picking process, why not try to add in lobby functionality on one of the existing sites instead of starting entirely from scratch?
I can easily see it being less work than patching it into TF2Pickup. The difference is massive and it's not just picking process it's also who hosts servers, how many queues are available at the moment and many other things.
On top of that TF2Pickup's codebase is not really flexible from what I heard, but it doesn't matter since it's just a different project, different goals, different audience, different way to go about serving for the similar purpose.