the difference is with roads you dont get a lot of good secondary effects, one lane is just like the next. benefits are linear with the cost so they balance out. but with typescript and software in general they can be exponential.

fast type inference unlocks brand new patterns that were too slow to be practical on the old checker. at least some of them will turn out to be useful for peoples projects. and its also great for legacy or less complex code bases that will get faster type checking for free.