I drive a car and a motorcycle. Like most cars, mine is automatic. Like most motorcycles, mine is manual. I wondered why this was the case when I decided to get my license and asked the instructor. Surprisingly, they do make automatic transmission-based bikes[0]. My instructor's opinion on the matter was "I'd only be caught dead on one of those. They're fsckin' dangerous as hell." explaining that control through a turn is handled by throttle/engine braking, rapidly down-shifting in emergency situations, and being able to tightly control every aspect of the bike is how you stay safe.

My thinking was that it was one of those things where "a new rider would be less safe because there's more to manage but an old rider would be more safe because they have a greater degree of control." I learned, quickly, that an 800lb bike with a big engine requires a lot more careful control through a tight turn than the "mountain-bike with a weed whacker engine" on it that we trained on--especially when said operator is 150lbs soaking wet. And while older riders benefit more, new riders are incredibly unsafe* until they've sorted out the "friction zone", throttle/shifting/gear ratios of their particular bike -- when you understand how your bike reacts from/between each gear and find yourself deciding between a dangerous white-knuckle-hard-stop[1] or a rapid down-shift, throttle and controlled escape, you're almost always safer escaping first, stopping second[2]. Escaping might require a downshift depending on where you're at. Left hand, left foot, throttle, release all happen at once and you hold on. :)

Having that level of control also makes it feel like you're doing something more than having a device move you from point A to point B* which makes it more fun, for me. Unfortunately, when it comes to a car, I have 4 wheels and do not have to manage lateral momentum as much around a turn. Having the half-second decrease in downshift time will give me more power but at the expense of an enormous amount of fuel and rarely to my benefit[3]. And just about every other feature of the car, except for the entertainment pieces, is designed to make driving as mindless/simple as possible. The only benefit, especially compared against modern/higher-end automatic transmissions--for cars--seems to be "it's fun".

[0] And, I'd imagine, electric motorcycles won't have power transmissions systems that require shifting.

[1] I have an ABS bike; similarly hated feature, because the thing it tries to save you from: wheel lock and a trip over the handlebars/under the bike, it often just converts into a less controllable version of the same result at a longer stopping distance. And being the stopped/out of control vehicle in an orderly set of moving vehicles is not good for anyone.

[2] Next time you see some dude on a crotch rocket like a complete jack-ass, pay close attention to context. There's been probably 10 occasions where drivers at the right angle would have thought I was being "one of those morons" when I was reacting to another driver who almost killed me because their phone was more interesting than moving the muscles required to check a blind spot.

[3] On four occasions since riding, I have found myself having to rapidly downshift, move to the left and ride the dashed line until I could get out from between two cars, one who didn't check their blind-spot before deciding to occupy the same point in space that I was comfortably enjoying. I would have been a sandwich in a car, but they'd probably have seen me, too.

edit: formatting