EDIT: I suppose there is a certain pressure to mess with the UI, so non-technical people will "see" the difference. Some changes have been genuine improvements, IMHO, like AeroSnap or the search field in the start menu, others have been disastrous (cough Windows 8 cough).
That's one of the worst offender. It opens a separate windows instead of searching in the menu itself, and returns a lot of crap (including web queries, wtf) except what it supposed to do: searching in installed applications. That can be done, at the expense of an additional click. Very poor UX by mixing concerns that belongs to different applications (Explorer and the browser).
I wonder if that's why even on a gaming desktop USBs default to "turn off power to preserve battery" which made my keyboard stutter, and I had to turn off this setting from Device Manager.