Nope, Ilfak gave us a license for it and as Binary Ninja devs we're using a legitimate licensed copy of Binary Ninja as well. All above board and we're hoping to add more commercial decompilers in the future as well as we can integrate them and the companies behind them are willing.
RE: Demand. We just got 2x the workers but as the easy coast wakes up I'm not confident it'll hold up too well, several of the decompilers are... VERY resource intensive so there's really no good way without an exorbitant amount of compute to scale to heavy demand.
Eventually a better queue system with better pre-processing to filter invalid things is on our todo list
EDIT: Site has changed in multiple ways in the last 30minutes I've been trying to submit my sample. Best of luck in keeping up with demand.