There are only two lights that matter to me: power and WAN. They let me see if there are problems that I can't do anything about through the browser UI. If there's no power, then obviously its a hardware problem and if there's no WAN then its an upstream problem that I cannot fix myself. All other lights are meaningless to me and I use the browser UI instead, like you.
(There is actually an option on mine that lets me turn off all the lights. (Except the power on light, dang it!))