I can imagine that if you have the money, that you would want to do something exotic like this. Same way like other people want to visit unique places on holidays. I do question their thought process when they saw the actual submarine before take-off. It doesn't really scream "high-tech" or robust from the footage that I have seen. However, even then, they cannot assess that being just a tourist in this situation.
I think there is quite some blame for the CEO of OceanGate (love the name by the way, screams scandal). It appears the framework was not in place to conduct these trips safely. Lack of safety features and backup vehicles to retrieve the vessel in case of an emergency are some serious oversights.
Keep it, store it somewhere. It is a good memory to what it ones was.