Doesn't this just lead to being steamrolled on every decision or would be conflict? Seems like it would work if the person is addicted to drama but not if they're happy to simply use you.
To me it seems like the crux of the technique is "don't engage in drama" but making yourself lesser to do that seems problematic.
I think it depends on the power dynamic. It’s probably easier to implement with family members outside of your home than your manager.
I believe the goal of gray-rocking here is to defend yourself against overly dramatic and abusive bullies which you are forced to have some minimal contact with (family member, co-worker on another team, friend-of-a-friend), not someone you have to deal and negotiate with daily. Those require different and situation-dependent strategies.
It's not making yourself lesser, it's basically "not taking the bait," which is very much a strength, not a weakness.