Many quantum foundation researchers keep emphasizing that For All Practical Purposes (FAPP), quantum foundations are irrelevant. They even invented an acronym for it! Does that mean that quantum foundations have no practical applications? If so, why bother working on quantum foundations?
I suppose there are two scientific reasons to look into the foundations of QM:
Every great physical theory has been proven wrong.
That's of course not (yet or ever) true, but if history is any guide, physical theories fail.
Newton's gravity is a prime example. Even Newton could see problems in its foundations, yet it is highly accurate and can be used to guide satellites and space probes. By questioning those foundations (and other things) Einstein found General Relativity, which works better than Newton's theory, and also solves the main problem with it.
Of course many (most?) physicists think that with QM 'this time its different'. It might be different this time, but likely not. Some hole could be found using thoughts on QM foundations. For instance de Broglie - Bohm theory gives one insight into possible experiments to perform that might show where QM 'ends'.