Not to mention that space is a normal printable character, while tab is a control character, like carriage return. Control characters have very well defined meaning, that is very different in different contexts.

As an example, and I hope this is not a new information for most, in many text terminals it does not mean "advance forward to a multiple-of-8 position", it means "advance forward to next tab stop", and you can arbitrarily set those (e.g. HTS/TSC on vt220)

If tabs or spaces are mandated at editor level, how are you editing Makefile or TSV files?

I really do not understand anyone, who is against having support for any possible indentation, controlled by the user as is necessary for each use case.