Bayesian decision theory is another name for Evidential Decision Theory (EDT).
Suppose we intend to meet a friend tomorrow, and expect an 0.5 chance of raining. If we are choosing between various options for the meeting, with the pleasantness of some of the options (such as going to the park) being affected by the possibility of rain, we can assign values to the different options with or withwithout rain. We can then pick the option whose expected value is the highest, given the probability of rain.