As you suggest, it smooths out your driving habits. You’re just focusing on balancing the accelerator with your desired velocity, that’s it. Need to go slower? Back off the pedal until you hit the mark. The regenerative braking kicks in so it slows down quickly, sort of like light-to-medium braking. It’s more responsive than you might think. Need to go faster? Press the accelerator as usual. No more going back and forth between gas and brake, which makes it less exhausting in stop-and-go traffic. You’re also maximizing regenerative breaking, so that’s increased efficiency and less brake wear. That’s particularly good when you’re doing down hill.

Anecdotally, to me it's just more fun. It increases range by relying entirely on the regenerative braking and relegating the disc brakes to an "emergency" role. For freeway driving in traffic it's also more intuitive, since you don't have to balance coasting/braking and can just ease off the pedal more to slow down quickly. Muscle memory can definitely be hard to break though, when I'm in a hurry I sometimes forget to enable single-pedal and drive for a bit before I realize it. The car we have (Chevy Bolt) has a separate regenerative brake control as a paddle on the back of the steering wheel for use in "regular" mode, but it's awkwardly placed.