[dspillett]

For the example given, would merging branch 2 into branch 1 then branch 1 into main achieve the same effect?

Perhaps not an option if you need to release the work in branch 1 before the work in branch 2 is ready/reviewed/etc.

[happytoexplain]

The point of this technique is to keep them separate. See the other comments about `--update-refs`.