Yeah, perhaps "obsolete" if far reaching. But if these are as good as they seem to be saying, the range from "Old fashion card wads" to "Flight Control Wads"... to say waxer or cut shells, and/or tradition slugs pretty much would seem to cover a log of territory with just a cylinder bore.
Certainly an appealing idea on paper. What the patterning board will show, I suppose, is anyone's guess.
Gonna have to find some time and space to experiment a little. Years gone by I was never a smoothbore person. These days, the flexibility seems more apparent to me.
Toss in a decent insert barrel and seems like you could do everything practical. The one missing thing would, of course, be the minute of angle extreme long shot.