It solves some rare edge cases where the destruction of the moved-from object must be deferred -- the memory is still live even if the object is semantically dead. Non-destructive moves separate those concerns.

There is a related concept of "relocatable" objects in C++ where the move is semantically destructive but the destructor is never called for the moved-from object.

C++ tries to accommodate a lot of rare cases that you really only see in low-level systems code. There are many features in C++ that seem fairly useless to most people (e.g. std::launder) but are indispensable when you come across the specific problem they were intended to solve.