I've noticed more and more devices specifying specific batteries -- e.g. my Spot tracker specifies Energizer L92s -- and it just makes sense that with these AA and AAA primary lithiums out there devices are taking advantage of them. Their open-circuit and under-load voltage is noticeably higher than an alkaline battery -- which is a nice efficiency improvement if you're boosting from one or two cells up to 5V -- and their leakage characteristics are in a different class.