Flashlights are actually where wall-plug efficiency matters most, because nicer flashlights are limited almost entirely by heat. Even if we got to 98% efficiency, going from there to 99% would nearly double the brightness that you could fit in a given size.

Power input isn’t a problem at all, by contrast. A tabless 21700 can do 70A continuously without breaking a sweat, which is over 250W, and that’s with a 5Ah cell, which is plenty of capacity. A 6Ah cell can do about 10A, and that’s plenty for basically any single-cell light out there.