Totally agree with the second video.....
Someone is gonna die using this thing .....even in scuba people die because they feel they can dive "outside" the envelope....for example, there will always be those that want to see how deep they can go with this thing and as long as they can keep clearing their ears they can probably go a long way, probably in excess of 100 feet. The problem is coming back up...Every dive we do, we stop at 15 feet to "gas-off" before doing the last part of the ascent.....normally 3-5 minutes,.to prevent the possibility of an embolism. There will be those that want to challenge each other to see who can go the deepest and will not have enough air for the safety stop.
Sport divers are limited to 130 feet and need only a 5 min stop at 15 feet but no matter how deep the dive is , (under 130 feet) you must do the 15 foot stop
I did chase a shark once, (wanted a good photo) , and went to 170 feet but then I had to do decompression stops on the way up, as well as the 15 foot stop. ( we all use computers that tell us the numbers while we dive but if doing a deep dive we also have the manual plastic charts as back-up)
The other big factor is the use of the bicycle pump to replenish the mini-tank !!! The second video pretty much sums it up and I agree with everything the fellow said
Something not mentioned is the possibility of developing a leak while pumping up the SCORKLE tank. Even if they get to 3000 PSI, a rupture would turn the gear into deadly missiles.
ADDED....What happens and you are horsing around underwater and someone kicks the bottle out of your mouth and it sinks away???? In group dives I have seen folks all trying to see the "creature" someone found and regs have been kicked out of another divers mouth......fortunately qualified divers, in fact all scuba divers mouth regulators are attached to their tank, which is attached to their body and getting the reg back is no problem . An arm sweep maneuver is done to get your reg back.
IMHO....Don't even think of buying this deadly toy....
Want to go under water..?? .take an authorized course, get qualified, and yes, complete personal gear is expensive, but you can rent complete and safe gear from dive shops.