Some of the electric bikes are more like electric trail motorcycles than bicycles. Those look interesting, but they cost and weigh more. The bicycles that have motors are usually more of a power assist. You still need to pedal some to get going, not much, and the electric motor then provides a huge boost.
A buddy of mine has a Rad mini, which is a 20" wheel fat-tire folding bicycle. With wide 20" tires it's good for more off-road, slower travel along a hiking trail or through the woods. Great for taking a trail to a deer stand, but less ideal for longer rides on paved roads. The fat tires are a tradeoff, they help on trails, off road, and rough pavement, but need more energy to get moving. That's where the motor comes in.
I have a basic mountain bike that I added a Luna motor kit to and it works really well for street use and is still ok for modest trails. I can pick up the bike easily and put in my car, and when the battery is removed, the motor has only added a few pounds to the bike. It has really good power, and still functional as a bicycle. Installation will take a few hours and you need to be handy. If you can't change sparkplugs in a car, then it's not for you. The Rad mini would be better for off-road utility use and is ready to go as-is. It's also lower than a typical mountain bike, which to me makes it easer to control on a slower, rough trail.