Wouldn’t say that it particularly boosts speed. I had a fairly big speed drop while learning to adapt.
Everyone’s different but it took a month of using it all day as well as doing typing exercises to get up to 70wpm.
I did the switch to an ergo keyboard because I was having shoulder and wrist pain and it seems to have helped rather than cured.
They’re both good but I’ve gotta say, I’ll not go back to a flat keyboard anytime soon.