>>57149570Except Tera'd Pokemon keep their original STABs
So for instance, a Ceruledge that goes Tera Grass gets the defensive advantages of being Grass type, while still having its Fire and Ghost STABs for offense
As for weaknesses, it still has Flash Fire, so the Fire weakness is nullified. That leaves Ice, Bug (both of which are countered by the Fire STAB it still has), Poison, and Flying as weaknesses. The only relevant weakness there is Flying
Tera types are a terrible indicator of a type's viability because the Pokemon retains its original STAB, stats, ability, and move pool
Physical attackers aren't going Tera Fire because Fire is a good type, they do it because it prevents them from getting burned
