BUT: Would this adjustment also influence the way Ardour “handles” the whole audio stuff “internally” - and thus decrease the “sound quality” of my whole project?
Ardour’s default format is also a floating point format, which means it has huge dynamic range, a big advantage during processing. The floating point representation uses a 24 bit mantissa, so there is no loss of precision in the conversion to float either.
Anyway, going from 32 to 24 bits is quite a small saving in disk space. If you’re worried about lack of space, get a bigger disk