Great idea! (But now it's an 80-pound bike... 😂 - yeah, they can be heavy, but at least you have the option to pedal back or someplace safe.)
LOL, the batteries do add weight, but...turns out that with 2 batteries, the bike can do 40-50 miles with a human onboard, and that is about the limit of what my wife can take! I have gone about sixty miles on my own with three batteries.
These are not top end bikes, they were entry level bikes that had good features for the price point (under $1000 each). We both enjoy them on bike trails, but neither of us will drive them on roads if it can be avoided.