"before you work out all kinks and merge the staging branch back into main"
Working out all kinks on an isolated branch is very hard to do. You need to integrate to hear the screams of the team you never expected your change would affect. So your choice is to integrate commit by commit on trunk, or to wad it all up into a single waterfall release from your branch to trunk, and then spend hours/days bisecting to find which commit caused the screams.
As jozzas said, feature flags enable your code to safely lurk on trunk before it's functional.
Working out all kinks on an isolated branch is very hard to do. You need to integrate to hear the screams of the team you never expected your change would affect. So your choice is to integrate commit by commit on trunk, or to wad it all up into a single waterfall release from your branch to trunk, and then spend hours/days bisecting to find which commit caused the screams.
As jozzas said, feature flags enable your code to safely lurk on trunk before it's functional.