Stonjourner is also one of the few Pokemon with access to Gravity, and the second fastest after Sigilyph in the regional dex, that plus Power Spot and Wide Guard makes it a somewhat unique, if gimmicky, Doubles support for teams that want to spam high power low accuracy moves or make use of stuff like Hustle or Hypnosis. I doubt it will use AV, unlike Kartana it doesn't really have a good enough offensive movepool and its ability means it wants to stick around for as long as possible, so forgoing Protect would be risky.