Well, I guess it *is* rather ... umm ... outside of the mainstream activity that most music/art lovers spend time examining. It actually isn't even something that many harp players do. In fact, many many harp players who are very good don't even bother to get involved in such activities. I guess that my first and primary instrument (the flute) gave me this desire to have an instrument that is not only in tune, but also happens to be relatively easy to play all of the notes that it is actually capable of playing -- and many harp players do not even try to get all of these notes out of their harp. But that is also not necessary to play really interesting and enjoyable music on the harp.
However, if you are interested in playing (for example) jazz or in exploring the emotional and artistic possibilities of the harp, then you most likely will have to go these extreme acts of modifying the little beast so that these possibilities can become available. Given any single 10-hole diatonic harmonica, say the typical C harp, it is actually fairly easy to play music in several different keys, for example in C major, G minor or D minor as well as a few others. But, again as an example, that D minor can also be played on a G harp or an F harp (just to name a few); but the differences in emotional feeling that the player can access with each of these harps is quite enticing.
With an instrument such as the flute, you buy a medium-priced model and you can pretty much play anything almost as well on it as on a $3,000 model. About the only noticed difference will be in the tonal quality -- and that is not really worth the price difference unless you are a studio musician recording classical music -- and most listeners probably would not even notice it! The differences realized by customizing/modifying a $25-30 diatonic harp are really almost dramatic and can be appreciated by most listeners.
Maybe I'm just an eccentric and spoiled (by the flute) guy ...
The most important thing to do with one's eccentricities is to enjoy the hell out of them :)