As already stated the "granularity" of the LED's is always in question.

I usually just check the battery state before I start flying ( after having charged them the night before ), using an Expanded Scale Voltmeter. After 45 minutes or more of actual flight time I may check the batteries again with the voltmeter, decreasing the intervals the longer I fly.

I typically use battery packs of over 1200mAh on the smaller planes and 2200mAh on the larger planes, so I'm not really worried about the first hour or so. The Voltmeter just lets me be sure that I've charged the packs properly and that they are maintaining their charge.

The LED's are amusing, but you'll find that you'll not be too enamoured of them over time.

The charge jack/receptacle and switch are another matter altogether.

You do indeed charge the batteries directly from the jack ( as well as check the voltage ) w/o removing the wing, so these are particularly important for my biplanes, where I rarely remove the wings.