[MiyamotoAkira]

Release integration branches bring the behaviour of big releases. The bigger the release, the bigger the risk, therefore the less you want to do it.

With release integration branches you not only integrate for release (which the bigger the release, the more difficult it is), but also now you have to integrate back from release into main (because bug fixes and what not). The longer that you have had that integration branch, the more likely that you have move forward the main code and the more difficult then becomes the back integration. So you end duplicating the effort.