Suspiria and Inferno are like Welles/Wyler and neo-realism as far as colour goes:
The US directors did long takes and deep focus in the studio, while their Italian counterparts did shooting on location. But there was an either/or at this time: use deep focus in the studio, or go on location.
Likewise. Suspiria did things with colour using obsolescent technology that could not be repeated, while Inferno used then-new technology to similar ends.
But Suspiria's look is different from Inferno's Each has its plusses and minuses: Suspiria is more intense, with saturation of one colour, while Inferno is more nuanced, with slabs of this colour and that.