other library doesnt need to set bin folder with all dlls added do PATH
If an executable has runtime dependencies, such as DLLs on Windows, all of those dependencies binaries should indeed be available in PATH.
So while other libraries might not tell you to do that, it is assumed to be a common knowledge, which is I guess why you don’t see this too often being mentioned in other libraries documentations.
But usually instead of adding them to PATH they are deployed together with that executable - that way it will be able to discover them without PATH manipulations. Modifying PATH to make DLLs discoverable isn’t a great idea in general.
and bin folder with all dlls added do PATH
…so that doesn’t sound like a good recommendation, and I doubt that official OpenCV documentation does in fact state that ha, they actually do state that.