The inverter type might be 'smart' too. Electronics can be used to detect and manage the condition of the arc making the welder easier to use. Older welders of the better class attempt the same with heavy passive components : not cheap, or particularly flexible, but they work well.
I'd say the difference in practice is like comparing the performance of an older petrol engine with vacuum distributor, carburetor, and coil ignition with a modern engine fitted with an EMU. The EMU delivers worthwhile improvements in mileage, emission control, starting, power, torque & self diagnosis and the engine is cheaper to make, but that doesn't mean older engines are rubbish. Far from it.
Dave