I think they're closer than you think. Not wanting to change beliefs can make you think things through properly in the first case IF you have a prior position of being susceptible to reason rather than just ignoring it. Similarly, not wanting to throw food away can increase your meal efficiency IF you have a drive to have good, enjoyable food.

Both of them can potentially reinforce a rational drive, even though in themselves they are irrational. But without enough rational purpose underlying them, they can become totally counterproductive. So if they suit you depends on a fairly empirical question of how you act with them and how you act without them.

It's worth noting that people who don't have any resistance to changing their beliefs aren't usually brilliant rational agents. They're people who just agree with whatever argument is presented to them at the time, because they don't think about things in depth, or really care about having accurate views, and therefore accord beliefs no weight at all.