I have a 2nd wheelset (got it used for less than $200, rotors included). It's 0.5mm off, so the mechs need adjustment as well as the brake calipers whenever I change the wheels.

Changing wide tires is quick (compared to changing narrow road tires), so the time savings wouldn't be much for normal clinchers.

But... tubeless calls for a 2nd wheelset. (Funny because I only went to tubeless on the 2nd wheelset. Shhh. Don't tell my wife.)