Use whatever you are comfortable with. That is the most important thing. My only issue is a shotgun is slow , less powerful and harder to get a pinpoint accurate shot with.
plus you are less likely to have it on you and with you most times unless you are one of those special people who roll strapped 24/7 then that does not apply to you
What handgun are you using that a shotgun is less powerful than!? Dang, son! LOL