Who cares if it's "legit"? If you like it, ride it. Unless you're doing sanctioned racing, there are no rules.
That said, there's a couple things about it I would be wary of.
On a bike that has the pedals shifted far forward--in order to pedal very hard at all, you either need a VERY solid seat-back to push against, or you need VERY solid handlebars to pull on. True recumbnts all use a solid seat-back to push against but with the Day6, the seatback does not look to be built very sturdy; my suspicion is that it's simply not a bike intended to ever be pedaled hard at all (especially considering the lack of full-range gearing). Additionally, the handlebars are tall and mounted on a low stem and if you pulled on them very hard, they would very likely slip in the stem and rotate backwards (so they're no good for pulling on to pedal hard, either).
Another issue is the saddle. The main reason these bikes have the pedals shifted forwards is to try to relieve saddle pain. If the pedals are not under the seat location, you can use a noseless saddle, and avoid the various physiology problems caused by the saddle nose totally.... so why then are two of the three Day6 seat choices conventional bicycle saddles? If you're redesigning a bicycle frame
to try to avoid the pain caused by a normal bicycle seat, then it really doesn't make sense to keep using the same type of seat. .....There are other noseless seats that might fit the Day6, so you may have other options there.
I've never rode or even seen a Day6 (or rode a Revive, for that matter) but I would guess that it's only good for very
casual (moderate-effort, moderate-distance) riding. Certainly there are people who only want that
, and I understand this..... but there's other choices that could do everything this bike does well, and without its limitations.
As an alternative, I would strongly suggest you look into the RANS crank-forward bikes. The RANs bikes are done better overall, and use a better type of noseless seat. They do start at around twice as much, but then, a bicycle that hurts too much to ride is no bargain at any price.