Yeah, I noticed that too…
And although there are nice keyboard shortcuts for changing the screen brightness (Fn+B, Fn+N on my UK Astro) and volume (Fn+C, Fn+V), I can't find any shortcut for changing the keyboard brightness. (Fn+Z and Fn+X would be the obvious choice, though anything would do. Does anyone know whether there's any way to set something like that up?)
Fn+Del, tap on Astro Settings, and tap on slider isn't the end of the world, but it's sufficiently disruptive that I'm not likely to bother very often.
Does anyone know how much power the keyboard backlight might consume (compared to, say, the screen)?