>The thing I don’t understand is why they had such a heavy
>use of CG for two guys in suits fighting. Why not just use
>stuntmen and good choreography?

From a movie standpoint, that was T’Challa’s third fight of the film, with the first two being just two guys fighting, and the stakes needed to be upped for the final fight. But also in universe, the first two fights were “natural” - no super suits and the power of the Black Panther was stttttrrrrrrrriped away. The final fight had both wearing BP suits, and both having the power of the heart shaped herb. So there needed to be some superhero battle type CG happening to differentiate that final fight from the first two.