The nice thing about the regen paddle mechanical control is the no-look ability at your fingertips to change the car’s response depending on driving context. There are moments when you don’t want the car to tip into a regeneration drag when letting off the power pedal and sometimes you feel the need for the “engine braking” to engage right away.
All the other EVs just have strong regen (B setting) or low regen and the selection is a preset you have to choose either on the screen or somewhere near the shift cluster and isn’t exactly a no-look control you can change on the fly. The older VW Golf EV used to have a stick where you can tap up and down two levels of regen on the fly and that was also a great experience but now buttons have replaced the stick. (Sigh, it was nice while you had it, VW!) The Chevy Bolt has one paddle but it’s designed like a brake-with-your-hands lever when depressed. Not quite the effect of stepping up or down.
In sum, the feeling of downshifting, such as into a turn, can be controlled. On the other hand, there is no need for “upshifting” if the EV had adequate power to get to a high speed. Tesla’s power and torque band is already covering high and low speeds with one gear, although an additional top gear would probably get them to a really insane top speed. I think Toyota’s goal is to eke out more range because they want to use less powerful motors where the power and torque bands would benefit from gearing. My dream is for Tesla to add mechanical paddle shifters and do what Hyundai does.