My two cents: I personally don't like to use a MTB for commuting. Nobby tires are one issue but for me it is mainly the geometry. The 26" MTB bikes I own have the correct frame height for my size but the wheel base is much shorter compared to my city/trekking bike.
Great for tight trails but not really comfy on long smooth city commutes. But I have not tried 29" mountain bikes which might be different.
But then you still have noisy uncomfortable tires. Or you switch to road tires and then the bike will be limited to light trails.
This is why I prefer to have a mountain bike for trails and city/trekking bikes for my commute. Quiet tires, fenders, chain guard, racks for panniers. I actually now added two recumbents to my fleet of commuter bikes.