It can be a very bad thing if applied to the tips of very fine or sensitive rods (match & light bass types for example) - along with things like those heavy tip rings can cause excessive wobble and tip-overshoot when casting, which can lead to increased crack-offs. It also ruins the feel of those kinds of rod; I had a Mk 1 TT Supermatch up until a few years ago built with those old heavy green Fuji rings and underwhipped all the way up and it really killed the crispness of the blank - it was much better rebuilt with lighter rings and no under whipping - felt like a different rod!
On most heavier blanks for mixed / rough ground you probably won't notice any difference though when fishing.
Gary