I editorialised the title as the original was clickbait, but the video itself is quite good. Interestingly, e-bikes are claimed to have lower emissions than acoustic bikes, although it likely depends on diet (the author didn’t specifically compare a vegan diet between the two types but did indicate that vegan + electric is the most carbon efficient form).
An acoustic bike is a joke term for a regular bike; think of the comparison between an acoustic guitar and an electric guitar
It usually works out pretty well with native speakers not familiar with the term. They usually have a moment with a blank stare thinking “what the hell is an acoustic bike?” and then realize all at once with a smirk.
As for your second question, acoustic becomes a good classification when talking to a group where electric bikes are the default, just like electric becomes a good classification where pure pedal bikes are the default. In a group where ebikes are the default they might assume you’re talking about throttle type if you say analog, or a pedal assist bike if you said manual. It started as a joke and became a useful term.
I’m a native speaker and my first thought was “wtf is an acoustic bike?” “Analog bike” would make a bit more sense.
Analog is the opposite of digital, which doesn’t describe an electric bike.
“Analog” has been used to say “the older, pre-computer version” since for decades now. It’s fine.
