The stash function is the least important thing in this module and giving one star because you don't like one function of whole set is just annoying.
Even that, using this function improves clearity for code. The Perl symbols table is directly accessible with typeglob prefix but it can be difficult to read and problematic if strict mode is used. Also the access to stash, glob and one of its slot have different syntax notation.
The Symbol::Util allows to manipulate separate slots of glob without destroying the content of another slots. So you can i.e. delete or hide the CODE without deleting SCALAR slot.
This module also allows to export some symbols between 3rd party packages and clean these symbols later. It is something like Exported mixed with namespace::clean.
Manipulating symbols table is often nasty. First of all, the description tends to be longer as opposed to your prospect. Second, it's hard to read as a matter of course. In which case, I'd like to recommend this module. The interface design and the documentation are both plain enough to use the module.