I don’t care all that much about cost or a little extra weight. I have Transmission on 10 of my MTBs (sold 1, used to be 11) and have installed it on several more for friends or other bikes I have sold. Never once had a battery issue and have never even considered batteries as a thought. It is just something I do as automatically as checking my tire pressure before leaving the house. So much easier for the vast majority of people to setup and maintain, looks cleaner and no longer a concern about messing something up when banging...