putting them on display in museums would make them less available for study.

Very often, it’s the other way around, museum are a storage plage for scientific/historical/artistic artifact and the be in display is a bonus.

Government own many objects that have an important historical value, and they can’t sell them (beside law, imagine the scandal if the French gov sell the mona Lisa or if US gov sell Neil amstrong spacesuit) so better having them in public display