To refinish the instrument reverses this very valuable feature. Having said all this, large patches of bare wood are also damaging to the instrument. The answer is judicious touch up which protects the wood, and retains the original finish and appearance as much as possible. I have read a lot recently about use of super glue on guitars. In fact, it is a great idea, providing you use them properly.
Super glue is a brand name for cyanoacrlyate glue.
On the other hand, it is quite brittle when dry, so it is not useful for major structural work, such as gluing braces, bridges or the like. It is very useful for fret work, such as gluing down a loose fret end. A recent thread on one of the guitar newsgroups talked about using it for finish repair. While this might be a good use in certain instances, it is not the best repair, as it will never truly blend with the old finish. I am concerned about humidity.