I used to not put the E break on my cars before unless it was a manual shift. Manual shift you pretty much have to or the car is essentially in neutral.
Only reason I started putting E breaks on automatic cars is because the one I got now (an older vehicle) was tending to slip sometimes when at a slight angle or especially on a hill (something none of the other cars I drove ever did). Better to be safe than sorry I guess.
Electric auto shifter does sound like a recipe for disaster. I work at a Chevy/Chrysler dealer and I remember hearing stories about people getting stuck at stoplights with their Jeeps. The newer ones power down the engine when you hold the breaks at a stop light or in traffic to converse gas and energy. It’s just the computer can malfunction so the car won’t get the signal to turn the engine on when you push the gas and you’re basically stuck on the road with no working engine.