@troubleMoney
Kinda? There is always crap to consider, most of the places that want rocks, particularly big rocks, as a feature of a garden or park normally aren't near useful sources of rocks lying around.
Also we spend a lot of time teaching people not to take stones from beaches and other natural spaces, and for good reason.
Also that first point? It's so much easier to fix a hollow concrete or reclaimed glass brick in place, much lighter and safer too.