[jzwinck]

Many Linux distros ship with /bin/sh being dash, but they also come with /bin/bash. A lot of scripts obviously depend on bash, so distro maintainers have had to either fix them to depend only on POSIXy "sh" or just put #!/bin/bash at the top.

The reason to use dash instead of bash is speed and to a lesser extent memory usage. The goal isn't to stop needing bash, it's to speed up boot times etc. Or at least it was five years ago when this transition was happening.