Features can sometimes reach a high-enough level of complexity that simply cramming the entire thing behind a single feature flag and calling it a day becomes widely impractical.
More modular feature control needs to be thought of and implemented beforehand. Since such scenarios happen quite often all throughout development, a more advanced form of feature flag management is needed.
Understanding the Flag Hierarchy
While the base concept of feature flagging remains untouched (in the sense that they still toggle stuff on and off), feature flags nowadays tend to act more like an interconnected web of toggles where they may or may not be dependent on each other to run. The main benefit of all this added complexity is the ability to use flags to control certain parts of a feature in a very modular and clean way.