Is the standard then that it's instrumentally rational to prioritize Bayesian experiments by how likely their outcomes are to affect one's decisions?

It weighs into the decision, but it seems like it is insufficient by itself. An experiment can change my decision radically but be on unimportant topic(s). Topics that do not effect goal achieving ability. It is possible to imagine spending ones time on experiments that change one's decisions and never get close to achieving any goals. The vague answer seems to be prioritize by how much the experiments will be likely to help achieve ones goals.