A bowline with stopper is a pretty common climbing knot in the UK [0]. I don't have the expertise to weigh into any debates about how safe it is, but I've seen a lot of people use it without incident, and there's no question it's easier to untie than a rethreaded figure-eight.
The yosemite variant is fine, but maybe we shouldn't take the world's best climber as a reference who has a lot more context and experience to make very measured tradeoffs:
> IMPORTANT: This knot is methodically NOT recommended and yes, it MAY untie while you are climbing. It can happen if your rope is new-ish (and that means it slides easily) and if you don’t tighten the knot with a lot of force. I am always splashing chalk on the knot in case of new rope to increase the friction and I do tighten it with a lot of force. The reasonable and recommended alternative, pretty common and very safe is double bowline. It is almost as big as eight, but at least it is always easy to untie.
[0] https://www.ukclimbing.com/articles/skills/how_to_tie_in_to_...