No it's not. Everyone who loves feature flags has never done serious work. The amount of extra work / redundant code that has to be done to accommodate different DB schemas / DTOs in addition to the "lol feature flag" on the front end is absurd.
Real world problems tend to be, at the very least, "add some new fields to the form" - at which point you are messing with DB schemas OR following bad practices like making fields that should have no business being nullable accept nulls because "who knows if the feature flag is on". This quickly destroys normalization and data consistency.
https://medium.com/swlh/worthwhile-modern-deployment-strateg...