I think that if a person shoots only one bow for a long time, it may be difficult for them to adjust to a different bow/arrow combination. I use a light draw weight recurve with carbon arrows for shooting in some 3D tournaments, a light draw weight longbow with wooden arrows in others, and switch to a heavier draw weight longbow or recurve with heavier arrows when I want to hunt. Because I switch frequently anyway, I feel comfortable with a new bow/arrow combination in a couple of weeks.
The real question, I guess, is whether I would be a better shot if I didn't do all this switching around? Probably. However, I really enjoy using different bows so I don't care.
Another thing you should know is that while I switch, every bow I use has a similar grip and a similar center-shot. I don't think I could successfully switch between a recurve with a contoured grip that is cut past center and a longbow with a broom handle grip that is not cut to center.