Whether people like the cover or not, it can't be denied the cover says something. Whether the band receive bad press or not, as a result, they'll still be the topic of discussion in the press, which is never a negative, in my opinion. No press is bad press, right?
It's the same with the Apple stunt. Whether people liked the album or not was to some extent irrelevant because the main consequence of the stunt was to generate world-wide attention and put the band back in the spotlight. The bands always been controversial too, so why should they change now, especially at a point where due to one reason or another, they aren't as popular in terms of the mainstream/radio as they once were.
Say they took the customary distribution/promotional route of selling the album directly to customers, and the album cover was another boring snapshot of the band, do people honestly think they'd be receiving as much attention as they are right now? No chance.
I applaud the band for the entire direction they've taken with this album. From the music, all the way to the distribution. It's made U2 the topic of discussion again!