It is very clunky and outdated-looking for anyone who's used to buttons.

I think the reason why American buses left them in was because it is considered rude to expect an American to stand up and walk three steps to push a button. Naturally, entering and exiting the bus is an unreasonable expectation, which partly explains the lower usage of public transit in the US. After all, Americans will spend several minutes driving in circles around a parking lot, waiting for a space to open up and aggravating themselves in the process, rather than parking in the next lot over and walking.