Di2 on an MTB….what a total waste of time. I mean seriously…electronics…on a bike…
Joking aside, I genuinely don’t like the idea of adding electronic elements to the key functions of a bicycle – it goes against the mechanical purity of the way it works, however advanced and complex that may be these days with e.g. air suspension, in my opinion. Lights etc. are different in my eyes as they are not core parts of the bike actually functioning.
I realise others may not understand this perspective, of course.