To answer OP's question: I think ghost ring sights are a good thing to have in close quarters. Anything that enhances your ability to place that very small spread more precisely is welcome. However, if you're already adept with a bead sight, do not consider it to be a dealbreaker.
Magazine-fed shotguns came out of competition, not defensive use or military/police. You're not going to throw on a bandolier of shotgun mags. If you reload at all, which is highly doubtful, it will be from a handful of loose rounds in a pocket or an open box on a shelf. Tube fed is fine, people have been doing good work with tube fed shotguns for over 120 years. It is a mature and highly reliable technology.
Magazine-fed shotguns came out of competition, not defensive use or military/police. You're not going to throw on a bandolier of shotgun mags. If you reload at all, which is highly doubtful, it will be from a handful of loose rounds in a pocket or an open box on a shelf. Tube fed is fine, people have been doing good work with tube fed shotguns for over 120 years. It is a mature and highly reliable technology.