My similar answer on Masto:
Yes. The growth has come in phases where X has done something massively “interesting”. Bsky is also still on invite-only stage so it’s not even open for all.
It lacks videos and some other features but I would say it’s main appeal: an alt. to X.
Why is Masto not able to bank on it is a really good question. My main guess is the architecture of separate instances that do not integrate into a smooth UX. The “a guest on somebody else’s computer” is too tech point for many.