MSilvia:Why try the filet mignon if you grew up on steak and cheese sandwiches and see no need to change?
Because you don't know what you might be missing. If you're in the market for a BC, do yourself a favor and try one out so you can form your own opinion. If you aren't in the market for one, and like what you have, stick with it.
... and lots of people do try it and prefer the jacket. The ease of adjustment means any suit/no suit combination without fiddling with a harness, trim can be fine, they can be comfortable, they have pockets if needed.
No more reason to switch to a wing than to stick with a jacket if it works for you.
Ive tried both (jacket BC and wing), currently i use a wing although there are some things with it i prefered with my BC. I know others that tried wings, hated them and went back to BCs. By all means try both, make a choice and use what you prefer but the original topic of this thread "why would anyone want a jacket BC" is decidedly biased by the original poster.