Controllability has nothing to do with stall speed. It has to do with the effectiveness of flight controls.
Yes, but most aircraft aren't very controllable when they're stalled. If you're flying an approach at 1.3Vso and your stall speed is 30 so you're doing 40, and the wind gust spread is more than that margin (say 10G20), you could have a problem. That same 10G20 is a lot less of an issue for an aircraft that stalls at 60 coming down final at 80.
DItto for crosswinds, if you stall at 30 and you have a 20kt crosswind, that's going to be a pretty serious crab or slip at touchdown.
Regardless, as I said above, airliners can fly in winds that keep single engine Cessnas on the ground, and Cessnas can fly in winds that keep ultralights on the ground, and stall speed is a big part of that.