One difference, is the turning safety for other road users. It’s like MUPs.
If a car is turning left, they are looking ahead of them for other cars and bikes. But on a MUP/bi directional lane, you sneak up from their blind shoulder.
It’s a regular close call I have with drivers, especially on MUPs.
Single lanes eliminate this risk. But yeah, have other downsides like winter snow, passing, side by side riding with friends, and cargo bikes all being impacted.
This is why 132ave is single direction, but wider than most singles. But you see the backlash that’s had too.