Because even 38 is miles better then 37, and we get six threads a day going OMG Y WONT DIGGAR SHO. PLZ HELP PLZ because they're in 38.
And, because it'll allow more freedom with detail, especially on tracks, without worrying about the horrible lag monster of the seventh dimension. and on top of that, with the new "freedoms" this allows, more people will be more motivated to make better things without worrying about superficial superstition.
Not to mention, up until now, the only reason given for not using 38 for leagues was because to get to 38, you'd have to "rebuild" the pack, which is exactly what you're doing now.