In my box of muzzle loader stuff from the late 1970s I have adapters and nipple variations to use all 3 primer sizes: small, large and shotgun, in place of both rifle percussion caps and musket caps, musket size nipples that use rifle percussion caps and rifle nipples that use musket caps. They all were briefly entertaining at the range, but, except for the musket nipple that used less expensive rifle caps, all of them were a waste of money. Washington's hunting equipment regulations then and now require a traditional percussion cap that is exposed to the elements during muzzle loader seasons. That negates any advantage these gadgets may theoretically have in the rain.
The set up that is the topic of this thread looks so slow to use that after initial experimentation you'd never again use them for target shooting. The only nitch I can think of for these would be if your ROA was your only self defense handgun AND you had a second cylinder with the same set up to do a switch cylinder reload. In that case these do appear to eliminate the occasional jam from a fired cap falling back into the action.