It does take longer, you yourself admitted it takes an extra bit of time to hover (.1 or .2sec), so the simple fact is it does take longer.
Also, you can have proper buttons even if it is scalable, you can have proper buttons until you’ve narrowed the mixer down a lot that it becomes impractical, then the hover buttons can come in, but the problem is when you’ve narrowed the mixer that much the hover thing doesn’t work properly anyway as the buttons overlap with the adjecent channels and you never hit the right thing.