Engineering is about making certain that stuff works before it enters production. If we claim to do software engineering, then that's just a simple part of doing our job. Everything else is just tinkering and hacking (the bad kind).
From an engineering point of view, yes. But not from the business point of view.
It's like a restaurant. You can make sure they new dish tastes like what you intended and isn't going to poison anyone, but until it's on the menu you don't really know if people will want to eat it or if it will be a success for the business.
This does make me wonder whether there's a place for a system where you split your usebase into N shards, and only deploy new versions to one of them; reducing the update rate from a user perspective by a factor of N. Of course, this means you have to maintain compatibility with N versions, but that's still better than N feature flags.