Bert's been around for years, but his website is much upgraded since the last time I looked several years ago. There have been prior threads here about his activities.
No reason, from a coin person's point of view. This is something you do in order to play mad scientist, or to baffle a machinist (I sent one a shrunken quarter and asked him to figure out how it was done). You should see what happens to a soda can put into that rig.