Yes, it really depends on the type of environment / app you are running too. If your app is stateful, uses lots of data, etc.. then feature flags can cause a lot of issues with inadvertent upgrades that have to be rolled back manually in things like user data.

Or you can have infinite permutations of feature flags if you don't flip them to be on for everyone quickly enough, and it becomes hard to test if[a&(not b)&c&(not d)] behavior vs if[a&b&(not c)&d] and.... you end up with too many to cover with testing well.