Gas water heaters often have control boards and displays with buttons. The only type that might not are the low-efficiency type with a pilot flame and room air intakes—but even those usually have forced exhaust fans that require some sort of smarts to know when to turn on.

Your typical $400-$500 tank style gas water heater has none of those things. It has a PCB with some analog circuitry to do sparky magic to light the pilot light. A gas/propane heater or stovetop is basically the same thing in a different form factor.

Tankless water heaters are necessarily much more fancy.

AKA low-efficiency water heaters.

Can you explain? Are you talking about inline water heaters as the efficient ones?

I have only seen the tank style in the U.S. So it seems to fit, though I guess you are implying those will get replaced by something better.

High efficiency condensing water heaters still have a tank.