It's LED fixtures that I have a problem with; they're very common since it's easy to make them in various shapes and things, but when a component fails more often than not it's a "replace the whole fixture" situation.
My parents have a ceiling fan that came with an LED light, which broke. It was barely under warranty for the LED part still and the manufacturer sent out a new light module, except they've changed the fan a little over the years and the new module doesn't fit on the old fan... they ended up having to send a whole new fan.
I'm not familiar with ceiling fan regulations, but regulations for recessed lighting (can lights) in some jurisdiction mandated connectors other than edison screws in new construction as a way to force out incandescent bulbs.
IMHO, pretty unnecessary, as once the PAR30 dimmable LED bulbs got good, I don't think many people would prefer incandescent. OTOH, I think they were pushing compact fluorescent, which I don't think ever got very good.
For new construction now, the LED fixtures can be mounted without a can, because they put out way less heat, and some of them are very thin, so they may not penetrate beyond the thickness of the ceiling, which is neat. But for retrofitting, putting a screw in bulb is nice and easy.
My parents have a ceiling fan that came with an LED light, which broke. It was barely under warranty for the LED part still and the manufacturer sent out a new light module, except they've changed the fan a little over the years and the new module doesn't fit on the old fan... they ended up having to send a whole new fan.