It's not a matter of hiding the fact that you're using Tor, it's a matter of whether it bypasses censors or not. There's a big difference between those two. Even if a censor is able to detect that an individual node is running Tor, that doesn't mean they can globally detect all nodes and then block them.
Tor's user numbers in China in particular are very low simply because it's just straight blocked. Private bridges and pluggable transports can get around that, but they're just not used at scale because that's just too challenging for ordinary users.
Tor's user numbers in China in particular are very low simply because it's just straight blocked. Private bridges and pluggable transports can get around that, but they're just not used at scale because that's just too challenging for ordinary users.