I also use feature flags when I'm 100% sure stakeholders or PMs will somehow find fault a certain feature after it's deployed, even though they're the ones who specified it, approved it and tested it in a staging environment.
Not exactly the thing that we should be using Feature Flags for, but it saved my ass several times.
On the other hand: this removes some of the accountability that non-technical folks have over software. This can be detrimental in the long term.
I have also found that for UIs the best thing to do is have a staged rollout approach.
Internals / Friendly users / Less friendly users / VIPs.
The blast radius & intensity of explosion is smaller on the earlier groups.
The groups themselves need not be fixed. If you have a stakeholder/group that demanded the new features, they can be in an early wave. Inevitably they may be the ones to find defects in it, so the sooner the better.
Not exactly the thing that we should be using Feature Flags for, but it saved my ass several times.
On the other hand: this removes some of the accountability that non-technical folks have over software. This can be detrimental in the long term.