I agree with you, but my point is more broadly that in reality we often don't go through the steps "1. estimate probability" -> "2. make a decision based on the probability distribution", because step 1. is so error-prone and intractable, that we typically jump directly to step 2. and try to limit our downside.
Of course you could look back and say, given the fact that I took some decision, what would have been my prior if I had used Bayes theorem, but my point is that we don't actually use it for taking the decision.
Of course you could look back and say, given the fact that I took some decision, what would have been my prior if I had used Bayes theorem, but my point is that we don't actually use it for taking the decision.