I agree, and my D800 is a very happy user of Wasabi batteries. Half price is attractive, however frankly, I have bought a D800 and a few high end lenses, so it's not about a few bucks. It's about not supporting the Nikon practice. The Nikon price is simply excessive gouging, and then they also disallowed any dealer from discounting anything (protects small dealers, preserves more Nikon outlets, but no concern for customers). Plus in some cases, the Nikon firmware is trying to do anything possible to detect and prevent us from using batteries that did not feed the Nikon pocket, which is NOT a performance feature, or a safety issue, it is a greed issue.
Lithium Ion batteries are a special case however. Very potent, and capable of destructive runaways. Lithium batteries are simply different. Safety regulations require a special chip in Lithium Ion batteries, called
coulomb counters, which determine state of charge by carefully measuring and accounting for all input and output current (this chip is not in other battery types). This chip prevents overcharging, and the chip disconnects the battery if excessive currents occur. Other than short circuit, it is not really about discharge use, it is about charging. Same chip can report charge status to the camera, and to the charger, but then which can possibly suffer interface differences. The chip does add manufacturing expense to Lithium Ion batteries, but not that much. TI chips are around $2.
So, cheapest camera batteries can work to power the camera, but the chip might not report charge status to the camera properly. I would avoid those, not because of not knowing status, but because they apparently omit the necessaries to make it happen. The proper chips are plentiful.
The Wasabi batteries do fully report charge status, and seem to work great. I am unaware of any reported issues.