Some thoughts from a 15 kyu player:
The score estimator is pretty bad. It sometimes marks obviously dead stones as alive. Since my counting skills are still lacking, I do use it to roughly figure out whether I am ahead, behind or equal in a late middlegame. For that, I have to use analysis to fill every gap and thus mark territory as mine or my opponent’s.
If there are ways to abuse the score estimator, deal with those ways (such as not allowing it to be used together with certain other features), not the score estimator itself, which despite its flaws, remains useful for weaker players.
Weaker players may also suffer from not understanding its flaws. In a recent game, (https://online-go.com/game/25514816), the counting estimator gave me zero territory at the top and I had to manually mark the five black stones at the top as dead. There was another game where I was losing but the counting estimator marked my large dead group as alive, giving me a win, and my opponent accepted the estimate, but out of fairness, I fixed it and took the loss. Even worse are counting estimator mistakes that I am unable to correct (see https://forums.online-go.com/t/scoring-bug-area-cannot-be-marked-as-territory for details).