[BlueTrain]

I think that you will actually be using the sights (almost) no matter how you are shooting your rifle or shotgun. If you are, as they say, indexing on the sights, then that's using the sights. The question is, is that sufficient or not for your purposes, which is presumably always the same, no matter what: to hit the target. However, part of this is that your form will probably always be the same with a long gun. You will have it on your shoulder, left hand up front somewhere and your head down a little. It is a perfectly natural stance and easy enough to get into quickly.

It can be different with a handgun and there can be a form of point shooting that does not take into consideration the sights. That would be any style where the handgun is significantly below eye level, including what is referred to as hip shooting. Just when you should shift from one form or stance to another is a rather grey area.

Some pistols have always been referred to as "natural pointers." I don't know if there's any truth to that but it usually includes the Luger and some would include the Colt Single Action Army revolver and so on. Generally speaking, a heavier barrel (that is to say, with relatively more weight in the barrel) will make a handgun seem to point better. The same can also be said for rifles that have longer or heavier barrels. Not only do they point better, or at least seem to, they will be steadier to hold on target. They will also kick a little less but the bullet's already out of the barrel by then.

The critical factor is speed, of course. With no speed requirement, there is no reason not to take your time with lining up the sights. In those cases, the target will usually be paper. With everything else, time is an element you have to take into account.