I only have the most basic understanding of engine mechanics so can't really speak the practicality of this engine...

I only have the most basic understanding of engine mechanics so can't really speak the practicality of this engine design versus others. Heck, I didn't even know what a 'rotory engine' was until I read this article. All I know I'd I'm glad to see engineers exploring engine designs other than your basic piston-fired (not even sure if that's the proper term) that has been around since steam trains.
https://www.wired.com/2016/06/tiny-engine-one-step-closer-powering-drones-electric-cars/