If 2% is a true figure (I can agree with that), lets put it into everyday commuting application.
For my 50 minute commute of 11.25 miles, clipless will get me there 1 minute sooner. 1 minute.

Now what follows is just my personal opinion on the subject...

As I said earlier, in a race this would make a big difference. If you commute every day like you are in a race, that's your prerogative but that's not my style. One minute isn't even noticeable to me. Plus, I have 20 stop signs and 20 lights to navigate through as well as school buses, city buses, motorists, pedestrians, crossing guards, and I'm sure other stuff that all have an effect on my commute time. That small of a difference wouldn't even register.

Let me put it another way. This is the commuting forum, not the roadie forum. If a newb was to come to me and ask if clipless would get them to work faster than good platforms (especially ones with good grip like I posted), I'd flat out tell them "no". The difference (if any) is sooo minute, it's not even worth mentioning. The only thing I would mention is that being clipped in will help you in climbing hills because they will help you turn the pedals over the top portion of your stroke and they will help keep your feet glued to the pedals when spinning ferociously down hill... and I would sure recommend then on a fixie for that same reason. But that's it.

Now regarding getting a boo-boo on your shins... are you ladies kidding me? (no offense to the real ladies, who typically have a higher pain threshold than guys anyway)
I guess If I'm walking the bike and happen to kick the pedal, that would hurt. Heck, some crank brothers or pretty much any other medal or even hard plastic is gonna smart. If I fall off the bike, hitting my shin on the pedal is the least of my worries. Being careful when the pedals are wet? Good advice for any platform, especially if they are plastic/rubber. Metal studs, not so much but still something to keep in mind.