But you are doing a merge possibly every time you push to the trunk, are you not? So if I got it right, the difference between branch based and trunk based styl

But you are doing a merge possibly every time you push to the trunk, are you not? So if I got it right, the difference between branch based and trunk based style is how long you let your branches to develop, both in time and commits. The one extreme is a branch for the whole release and the other is a "branch" for just a one commit. Feature branches would be something in between. Now the problem with long branches and painful merges sounds like a communication problem between the master and the branch, just at the level of the code. We know that at the level of people timely and terse communication is key to a successful project. So the same would kinda make sense at the code level too.