If there is some particular moment at which the least possible beard growth is desirable, for instance for a photo shoot, then I can see the advantage of the closest possible shave.

I was going to write “I've heard that in some cultures, failure to do that is considered such a faux pas that they have a name (‘five o' clock shadow’) for that”; then I looked up http://en.wikipedia.org/wiki/Stubble and found out that's something marketers made up. (Well, after knowing about De Beers and diamonds, that doesn't surprise me at all.) FWIW, that's not the case where I am: stubble is quite widespread, and I only shave a couple times a week.

If wet shaving takes something like 10 minutes

It's not like I've ever timed myself while shaving, but I'm pretty confident it takes much less than that. Anyway, I wear a goatee and sideburns, and I find it very hard to give them a decent outline with an electric razor alone.