Yes, that's the general idea - and it works pretty well.

It can also be a huge PITA. The fallacy is that a "feature" is an isolated chunk of code. You just wrap that in a thing that says "if feature is on, do the code!". But in reality, a single feature often touches numerous different code points, potentially across multiple codebases and services/APIs. So you have to intertwine that feature flag all over the place. Then write tests that test for each scenario (do the right thing when the feature is off, do the right thing then the feature is on). Then you have to remember to go back and clean up all that code when the feature is on for everyone and stabilized.

It's a good tool, but it's not an easy tool like a lot of folks think it is.