LEDs can light a medium-sized room with <5W. That's incredibly energy efficient.
If you asked me to build a house and I threw away more than half of the bricks you'd call me crazy. But when it comes to leds it's called "incredible efficiency". It's only efficient in comparison to the other options, not in any objective sense.
Now sure there are subcategories where 100% efficiency is the maximum theoretical efficiency (like the carnot cycle limit of 37% for heat engines), but that's already misleading info if not specified.