There is a ton of data that proves this particular harness has been engineered to run safely when installed in a proper manner. While you might not do it, it is perfectly fine for someone to do it. There are things that are perfectly safe and socially acceptable that I would never do.
Schroth does manufacture some harness sets which are fully street legal, and even carry legal NHTSA/DOT approvals, yes, IF the 'tail' strap(s) are mounted at the correct, injury avoiding angles, and securely to either a roll bar, harness bar, or the floor pan of the car.
I am not sure if NATYPE's Quick Fit Pros fall under this approval or not, but there is one very competition-like, and appearing set which does (besides the fully legal Rallye 3/4 setups), due to it's center lock release button, vs. a full competition harness's lever 'dial'.
Schroth's whole ASM (anti submarining) tech feature built into the straps is also part of what allows them to have that street legality, albeit yes, overly zealous LEOs might still pull you over for having them, but you will have the official 'papers' to show to get out of that ticket, whether on the spot, or in traffic court.