In the future we could make a separate ds_debugstr_reftime function, like how there is a global debugstr_fourcc function and a specific mf_debugstr_fourcc for Media Foundation. Do you see a better way to do it?
The problem isn't that we'll need a separate function for dumping REFTIME; float printf is perfectly fine for that. The problem is that calling this function debugstr_reftime() is potentially misleading.