Comparing pure State Machine approach vs. Montage Mixture

Hello, I’m playing with animation blueprint for a while now and I have some questions about it, watching what epic is trying to do in their examples and tutorials, I think using montages should be a good thing, they are epic after all, but I see that everything done using montages can be done using State Machines, the good thing about it is that all animation controlling code is at one diagram with the ability of using sub diagrams and it is very readable for other people too but using montages forces you to divide your controlling logic between both animGraph and eventGraph, the fact that only one montage can be played at the time makes it harder to design the flow of controlling logic.
My guess is using machines too much is not a good practice for performance, but it is only a guess, concluding I found no advantage in using montages instead of State Machines. I saw First Person Template project and using montage to just loop shooting animation seemed pointless, or even usage of montages in shooter game seemed like an overhead. I’m just trying to understand the ideal mixture. any ideas? can someone explane where exactlu I should a montage?