If there's no scoring system to prove my opinion that Burstyn deserves it, then why did you confidently assert that Roberts "deserved it"?
I think if one watches the two films it's pretty undeniable how much more complex and challenging Burstyn's role was than Roberts'. But yes, both were good, and it is my opinion. I'd nonetheless marvel at someone opining confidently after seeing both films that Roberts was more deserving of an award for achievement in acting when Burstyn was also competing that year in that role.