Nobody ever said not-disabling backgrounds makes you more pro. Get off your high horse. Some people actually like the atmosphere that the background image and storyboard changes add to the feel of the map. In maps like
http://osu.ppy.sh/s/33911 the storyboard really makes the map a lot more fun to play and if you're removing it then you're missing out on some of the nuance that goes while playing it.
If you really wanted to remove distractions completely, you'd disable the mp3 too. The song does little to help your timing, and it can do more to confuse you on most maps than help you. Face it, you can play Osu perfectly by visuals alone, and it is also more reliable to play like that.
Again - if you just want to go with maximum efficiency to get the best play results - then why stop with skin and background? Replace the mp3 with a blank one too. An inner metronome will be way more accurate than a potentially incorrect offset and ambiguous song-beat mapping syncs that many maps have. Don't go and claim that backgrounds are
'only a distraction that increases the difficulty by making beats harder to see'.
For many players,
a good storyboard is not a distraction
at all and it makes the game more fun. There are many maps where the storyboard is badly done, has annoying flashes, pointless effects, or a myriad of colors in the background image that makes it really hard to see beats - but in those cases, it's the mapper's fault for making the storyboard wrong. It doesn't mean all storyboards are globally bad. It's on the same level as having maps with incorrect timings, and yet you still play with mp3 enabled, right?
Nearly all maps before 2011 feel completely off-timing for me and I find that a lot more distracting than a flashing storyboard.I'm in favor of having an option to let people disable backgrounds, similar to NoVideo. I would rarely use it myself, but I see no reason why not just let anybody play however they want. However I believe the reason peppy doesn't want to add this option, is because a lot of people would instantly leave it enabled without even trying to play with storyboards, and because of that mappers would lose motivation to actually work on interesting and good storyboards - and then people who do like playing with storyboards would get shafted.
If/when OSZ2 comes out, it would be nice to see something along the lines of having a NoBackground mod added, but only allow to use this mod for each map difficulty after you at least cleared it once. That more or less solves the problem. On one hand mappers would still be motivated to make good storyboards, because if they're bad people would complain that it's unplayable, and on the other hand players who like to disable storyboards and maximize their efficiency and scores (which would require practicing a map several times anyway) would be allowed to do so with no background as a legit game mechanic.