I drive a Volt and I’m convinced this configuration of car is what many Americans should be buying until battery manufacturing ramps up and EV fast charging infrastructure is widely deployed. It gets 45-60mi range but it charges just fine overnight from a 120v plug. Most of the time it’s an EV, but we need the extra range several times a month for longer local trips or to visit family in a nearby city. The gas engine requires very little maintenance because it runs infrequently and at optimal RPM and load, it weighs less than a 200mi+ range battery, and (for now) it’s easier to manufacture from more common materials.

The current Honda hybrids (Civic for sure and I think CRV also) work kind of that way - in slow speeds it works like a series hybrid and only in freeway speeds it connects the ICE to the wheels.

The claimed mileage is similar to Toyota's planetary power splitting thingie, no idea how it works in the real world.

You could also say that hydrogen fuel cell vehicles are series hybrids, since the fuel cell mostly charges a battery, which is much more flexible in what power it can provides and can be recuperated into, unlike a fuel cell which is one-way.

Honda e:HEV, Nissan e-power are series hybrid system afaik. It was considered to inefficient system in theory, but it seems fine (but not so great as THS), drive feeling is very close to BEV, and can share development resource with PHEV/BEV.