I hadn’t thought about that, but yes, if one string is one tone below the next higher one, it allows you to slide up that string to form the main open chord. I imagine it was first used by Davey Graham in She Moved Through The Fair and Bert Jansch in First Time Ever I Saw Your Face, but since then has become a bit of a sonic cliche, probably because it’s such fun to play. I daresay you can say the same about Sawmill tuning on five string banjo (gDGCD).