I'd want to run at least 100 thru and that would be close to $100 just to test reliability and yeah, most aren't going to bother doing that. Heck, most don't even buy more than one ammo to see which patterns better in their shotgun.
Sure the Opsol adapter improves reliability when using the minishells, but I don't think it completely eliminates issues and the Opsol only works with Mossberg shotguns. Given how much of a run there was on shotguns last year, I don't think I'd recommend to someone looking for a super low recoil option to go with 12 and minishells because they may not be able to get a Mossberg when a panic hits.
I'd say until someone makes a shotgun built to run minishells, every shotgun will be suspect with them, even Mossberg.