Honestly, it'd drive me nuts having to replace yet another battery on one of my digital gadgets. I think I'd so rather stick with your run the mill ruler we've been using for ages, but maybe it's just this obsession with vintage gadgets lately has talkin'. Quite frankly, looking at the digital ruler just makes me think of this "Technologic Overkill" video promo shot for the iPhone a few days back.
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I can't tell whether it shows a starting point... so where is your frame of reference?
This might be the most unnecessary thing I have ever seen.
So it measures from the end of the ruler to where it is being touched by any writing instrument?
What if you are just measuring something and not drawing something? Plenty of times you might just want to size something up. You'd have to press the edge at the point you are measuring to. And also, a regular ruler with markings lets you zoom into say 6 inches if that's what you need. Here you need to guess and then see the reading, then adjust and check reading repeatedly until you got what you want.