In agreement with @SK53 I consider these to be more “subway” stations than “tram” stations, not just for the renderer. tram is also not completely correct for our premetros: the parts where they go underground are not really tram lines. Specific tagging for premetros in an option, though I worry it may be a bit too specific: according to List of premetro systems - Wikipedia there are only a handful.
I do agree that station=subway with *=tram is weird, but I don’t find it problematic. However, I did the change to subway opportunistically and can roll it back if need be.