I will often vehemently support clipless, notably MTB pedals/shoes, for commuting. And I really do think they're unbeatable for on-bike handling, comfort, etc... and decent for running into stores.
But my main bike I've been commuting on for the past month has old, crappy platform pedals. And I really like it. Everything about the bike is different though, I go slower, it's a beater so I'm comfortable locking it downtown, etc. I have a completely different mindset on this bike, and it suits me right now.
Being able to just hop off your bike you were cruising on and lock it real quick is a lot nicer than hauling around on your expensive CX bike, and then swapping a bunch of clothes and stuff.