The concept is that the air is pushed forward instead of rising straight up
Radiators create a convection current, hot air comes out the rad, goes up to the ceiling and works it’s way across the room, cooling on its way and at the other side falls as cooler air and then gets drawn back towards the radiator at low level
As that circular motion continues, the air temperature raises.
The question is whether the smart fan overall pushes more warm air at a lower level, I’m not convinced….but it might work. I guess if it pushes out warm air towards you, which reaches you before going upwards, it might create a greater perception of warmth. I’d guess you have to closest to the rad to feel that, in which case you might be feeling the radiated heat anyway
It could heat up room faster by accelerating convection currents