Yes, the breathing time of the spare air units is less, however, the Triton system is strapped to your face, whereas a tank doesn't need to be. The weight of the tank is a non-issue because in water, you don't feel the weight... and size isn't an issue unless you're in tight places, which would be absolutely insanity with a system like Triton (even if it worked). So what is the benefit of Triton over a compressed air system? With air, you can literally just connect it to your existing air tank and fill it. Around here, an 80-120 cu-ft tank costs $5 to fill, and there are lots of places to choose from anywhere that you might want to go diving.
Suppose the thing somehow works... then buy in cost (I doubt someone could purchase a complete SCUBA setup for $299 with similar dive time), size, 'coolness factor'.
For LO2... how would they get around the storage/hazard issue? Maybe I am wrong but it seems that is a pretty extreme use case for LO2... being in the sun, being bounced around on a boat, being in water. That seems to be pretty huge temperature swings and LO2 is problematic (at best) to store/transport even in much tighter controlled conditions, no?
Youve probably seen people walking around with lo2, something like this
Lo2 Portable Storage. This is a medical device with additional regulating components but has a similar storage volume they would need and has a storage time of 9 hours. Being a medical device, it costs $1,000 but the dewar inside of it probably costs a fraction of that (but I dont really know).
Lo2, your always going to end up less than when you start (unless you somehow keep the temps way down with another cryo fluid or device), but you can get the boil off rate fairly low with good insulation and some pressure; you'd have to bring more than you're going to use and you'd probably have to use it somewhat quickly but it can be done.
Actually getting the lo2 is a whole other problem and I doubt you could do it at a reasonable cost except for local pickup from supply houses.
As for LNO2, you can already get your air tanks filled with "Nitrox" for diving... so that goes back to me not really seeing what Triton's system supposedly brings to the table? They talk about some sort of chemical oxygen generation and liquid oxygen "working in conjunction with gills" (whatever that means) - so at best it's quite a complicated setup compared to just taking a tank that just needs a regulator and that's it.
So even if it could work, the only benefit they are offering is a smaller size, but at (significantly) higher cost and less reliability and much more dangerous. I just can't understand the backers mindset.
Supposed the lno2 system actually works (and supposed it is what their system is) at the price and form-factor they're advertising. Then for the LNO2 system it would have some pretty major advantages for a consumer. Cost is the big one, compactness, coolness, shippable consumables... are all factors generally important to consumer.
Also..why not just make a more advanced snorkel? Were talking 15ft.. Float on top of water, possibly pump/compressor, some valves, run a line or two down.....swim for hours or more... and probably could be done for $299.