The way I use my OneMotor is I turn the main battery button on at the start of the ride, then I use the button on the handlebar controller to "pause" the system. When I do that, nothing is touching the tire and there is absolutely zero drag or effect from OM. I purchased the PAS wireless controller as well (brilliant) and if I reach a point on my ride where I need/want some assist, a single button push on the handlebar controller reactivates the system and it engages the wheel. It then runs at the selected PAS level (there are 9 levels) until I push the button again to deactivate the assist. It is seamless, not jerky at all, and works perfectly for my uses. OM has two different size batteries available and I chose the smallest one and typically can do a 20 mile ride with intermittent assist.
I sold my car and I use my bike(s) to go everywhere. For example, I ride to my doctor appointments. On the way there, I'm more interested in speed to reduce my transit time and not arrive sweating grossly, so I use the assist on level 1 almost the whole way there. On the way back I use it just on the hilly parts. Total trip is 16 miles and I usually end up at home with around 25% battery left. Hopefully that give some idea of
how it works.
The other thing I love about it is that sending it back for software updates (or repairs in the future) is easy as you are not sending a wheel. It goes USPS priority mail medium box, $17 (not sending the battery of course).

But maybe you don't need all the fancy stuff and software. As I said, having two bikes (one pulls my trailer for shopping) makes the OM cost very reasonable, but for a single bike maybe not. If it's your first time trying an e-bike, maybe a cheap PEdrive might be a good start. They are so inexpensive they are almost disposable, lol. A good way to test it out. You might decide you want a more permanent dedicated system (hub or mid-drive) after using it.....or not.