For live streams, yes, DASH might be super useful.

For on-demand movies, I'd like to it to buffer in advance to a sufficient time length, but don't stutter anymore after that!

Hell I would rather lag for 1 minute for live videos instead of DASH.

I think it boils down to personal habits, would you endure constant small problems with quicker progress, or would rather suffer at the start and enjoy a smooth ride afterwards.

DASH is just a format, you can use it however you like, e.g. prebuffering parts or the whole movie ... that's the flexibility of an open standard. there are a lot of open source players or also commercial ones such as www.dash-player.com, which exactly enable this flexibility.

and other people live outside of third world US internet bubble and have access to modern networks with no data caps and decent speeds.