If I were a repressed citizen of China, the last encryption app I’d use would be a commercial one. There are alternatives that don’t involve Apple or any other commercial enterprise. The simple act of downloading a commercial app would make me uneasy.
Removing commercial VPN apps from a public store is mostly a who-cares, as far as I can tell. It’s unfortunate, but it’s not going to stop anybody in China who really wants to use encryption.
I thought you couldn’t side load apps on new iDevices. Do you have an alternative if what you want isn’t in the app store?