Comments by "GunFun ZS" (@GunFunZS) on "How Does it Work: Open Bolt vs Closed Bolt Firearms" video.

If you recall his interview with jim sullivan, his product improved AR15 variant had that feature. There have been several other guns with that. Most of them start out with the bolt switching feature, but after adoption, people figure out that the gun is either useful as a semi auto, or light burst, or it is useful in full auto, and it gets simplified to suit whichever role is preferred.
1