Thats completely useless. I mean like 100% useless. The game gets downloaded anyways. A plugin needs to be installed, the user has to have the right permissions to toy around with the browser, a binary has to be downloaded anyways and so on.
I'd rather download an installer or a zip file than some browser plugin for every engine there is, bloating up my beloved browser more and more and leaving back dead data I wont be using anytime in the next years anyways.
A browser game is a browser game, but Acknex with a browser plugin is NOT a browser game. Thats just a standalone application that gets rendered into the browser. Which is totally pointless.
Besides, already had this like four hundred times here.

(Though I feel sorry for Quadraxas, as I know how it feels like when contractors insist on something stupid.)