I was wondering why the Yoshi bike isn't popular for 200cc NI... I would assume it could potentially be better because you could take better lines while having a decent mini turbo stat + faster MT charging

Inside drift is slower than outside drift on almost all courses. It has the same mt stat as wiggler and is worse than biddy, so it doesn't actually have any advantage there. You can get fairly close to outward times with inward, still, but it's more difficult and is a big disadvantage overall.

The Yoshi Bike is one of, if not, the fastest inside drift bike, but this game isn't MKW, so it is slower. You can still get decent run times, but Mr. Scooty and Biddybuggy are faster because of the way they play on the courses, and because their stats are better than the Yoshi Bike or any inside drift bikes.