What does a "final burner" mean or accomplish?
For me (and this is me personally, so I won't appreciate anyone flaming on me with their opinion) I will occasionally (usually rarely, but the last few weeks I've felt like using them) do cable flyes - not crossovers, but same kettle of fish - to bring my chest to complete fatigue. To enjoy the pump, and burn the muscle.
I don't often want it/need it/use it (again, with the exception of the last few weeks) but it will allow me to dredge that last little bit of muscle building exercise out of my chest when I can't move my dumbells or a BB anymore.
You're a smart guy, and I know that you understand what I'm trying to say here - whether you agree or not is completely irrelevant. One of the most resounding truths in bodybuilding is finding what works FOR you.
Occasionally, it works for me. And I KNOW it works for others. Not all, but definitely not just me.
A side note (and something that is of little importance to the thread, but is of GREAT importance to me): I love going to the gym. I walk in those doors, and it feels like home. If I like an exercise, I'll embrace it. If I hate an exercise, I'll simply endure it. Or, I'll make it my b1tch and learn to love it. Cable Flyes is neither of these. If I want to do it (or feel that I would benefit from that last little bit of fatigue) I'll do it.
It works for me. And in my honest opinion? That's what's important.