I think the question was discussed in the thread about the Rollei Digibase C-41 kit, which also claims a better temperature "latitude".

The "expert opinion" was that C-41 is C-41 is C-41, there is no shortcut, the chemistry involved requires those temperatures for best results.

That doesn't mean that processing at 20C gives awful results. It just depends on the photographer's attitude toward quality. Given constraints, or to try the thrill of home development, good enough can be good enough. But some quality is certainly left on the table.

A cheap, approximate hot bath, even if not perfectly consistent, is probably conducive to better results than a 20 development conducted with great consistency.