I wear shorts nearly 365 days a year. An LCP is one of the few things that is easy to conceal and can be quickly pocketed in its holster.
It's not bulky, doesn't limit my movements, and I don't have a heavy gun rubbing up against my back all day long... some days I wouldn't CCW because it's too hot, the gun too bulky.
Subcompact lets you have a gun when you normally wouldn't carry one. That's worth it to me. That and the LCP is shockingly accurate at 5-10 yards--if you don't mind recoil.