Scorer, shooter, hard to compare as everyone has their own definition of what these mean. Looking at last season (2020-21):
Scoring:
White 15.4 pts in 30 min
Richardson 12.1 pts in 30 min
Shooting
White 41%/35%/85%
Richardson 43%/33%/91%
Not much difference really. White got to the line more (3.2 vs 1.8 FTA). Rebs and assists pretty equal.
I am starting to think that this trade was really White for Langford and a pick but then the Celtics wanted to dump salary to stay under the tax and didn't see a need for Richardson so they used the pick swap to get the Spurs to take on Richardson. Richardson can be traded in the offseason easily enough. I guess they don't really have a need for Richardson, certainly not worth paying tax for him but he is a useful player. Unfortunate if the Celtics really did just dump him. Dallas has the salary space to just kind of "store" Richardson and then trade him for what they can get in the offseason. I doubt he is in their plans either.
It is a strange trade. More just repositioning than a trade that really improves your team. Let's hope White starts hitting his 3s in the 34%-35% range as he has for most of his career and maybe it will turn out to be an upgrade. The picks (low 20s this year and maybe worse), Langford, Richardson, none are big losses so even if White doesn't pan out, not a lot of risk in this trade. And chances are that White will start to shoot better than 26% from 3.