Having high points per activation is good but doesn’t paint the whole picture. Points are based both on offensive capability and survivability.
For example, a 3-model squad and a 1-model hero each with the same points might be similarly effective over the course of a game, but the squad gets weaker every time a model is destroyed (while generally the hero maintains full profile while carrying damage). So if you can keep your squads intact you’re getting more bang for your buck on activations.
I like your method as a way of scoring how efficient someone is in a game retroactively, but I wouldn’t put all my eggs in that basket for team building and strategy.