Switch power ratings

Anyone know why some switches have separate power ratings listed for incandescent bulbs and LED/CFL bulbs?

Maximum Loads: 960W Incandescent, 150W LED and CFL bulbs

My initial thought was that the type of bulb shouldn't matter - a Watt is a Watt. But, it seems like that might be too simplistic if manufacturers are calling this out specifically.
A quick google search didn't turn up anything useful, but I'm far from a search oracle.

Resistive versus inductive/capacitive loads.

This is as good a quick / not overly technical discussion as any:

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Resistive loads (incandescent bulb) act different than an inductive load (fluorescent with a ballast or motor). The inrush current acts different, and you will have some inductive kick off a ballast or transformer.

One thing I know they have done different is cut power to dim on the leading vs trailing edge of the A.C. pattern, I don't remember off the top of my head which one is better for inductive vs resistive, and there are some side effects like noise that can be caused by one of the methods.

Anyway, there is a difference, and they do mean it when they say "X" watts for one type, and "Y" watts for another.

The search terms you want are inductive load (or resistive load) dimming triac.

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It seems like both of your answers imply the limitation is on the dimming capabilities/performance.

Would you expect an on/off switch to also have different wattage limitations depending on the load type?

It wouldn't surprise me to have different ratings. I would suppose it would depend if they are using electronics to switch, or a relay/contactor.

In the USA, we have UL listing which should test for safe limits on switches, and I believe the Canadian (CSA) and EU (CE?) have similar testing agencies.

Yes, but it is a little less important. Depending on the circuit design, there might not be enough resistance in few/low wattage LEDs to meet minimum voltage requirements. If they used a relay it wouldn't matter, but relay based switches are less common these days.