You usually get a few more days to hunt. Whether it's worth it or not is up to you to decide.

Ours is 3 days plus the second half of the firearm season. I got into it originally just to try it and ended up getting hooked. Now I only hunt with muzzleloaders even during our firearms season (Slug guns, handguns, or muzzleloaders only). We also have a late firearms season in January for counties with too many deer and everything legal in the firearms season is legal then plus that is the only season ML handguns are legal since it was originally pistol season. I got a ML handgun last year specifically to hunt that 3 day season with. I didn't get anything with it last year but I'm sure gonna try again this year.

One thing with a muzzleloader you need to consider is your range is pretty limited. 100-150 yd shots are normal. Some guys can push it to 200, but that requires a lot of dicipline and practice. Further than that is beyond 99.9% of the hunters out there. There's just too many things that can go wrong.