He does a really good job on this aspect of testing.  As many of the responses that follow, there's significant interest in OTHER tests which are equally important, and frankly, if he DID, I think an accordant video would be something that (if I were doing safety training), I'd actually offer him a check for gentleman's license for a training class.

I'd make a suggestion of slight change for his test rig-

Replace the 'toggle' setup at top, with a roller, so that it doesn't lean and bind...

Put at least one more turn on the ratchet, to get away from any point-bind (the slip through shaft is not a constant, so it MAY cause a skew in data)

Put the instrument on a shelf hanging UNDER the table, get the S-type load-cell on a mechanical link UNDER the table, and put a hydraulic damper on the mechanical link.  First, because the unrestrained strap hardware could damage it, and the load-cell cable, and second, the S-type load-cell is undergoing significant shock, enough to change it's zero-offset linearity after each shock cycle.  It may be indicating RTZ, but the shock induces fatigue that makes it errant without applying a calibrated load.

Change to an instrument that does integral peak load recording.  Yeah, he's doing this on a budget, and it's a cheap imported instrument and cell... borrowing a good used instrument isn't difficult if you call any neighborhood scale guy.

Last... setting up each test, zip-tie the strap hook to the table eyelet... so that it doesn't launch.

and for other tests:

A well-UV exposed strap... and some worn, nicked, driven-over straps... Hydraulic or motor oil, grease, anti-seize, paint...  Not having time to actually FORCE a UV exposure, just grab a few OLD straps and visually LOOK for problems, mark 'em with a sharpie, and give'm hell to see if/any of the flaws are incipient failure points.  (actually, because this will eat up lots of straps unnecessarily, a second fixture that clamps a sample securely would work great, a hydraulic ram pulling on a about a foot sample of the previous test straps' unloaded 'tails' would be perfect... and use a hydraulic pressure sensor, rather than the S-type)

Adding one twist to stop vibration, in the long run, extends the life and safety, because that vibration is a stress in-and-of-itself.  What doesn't arise from simple abrasion at the wrap-over point (With, or without Strap Protectors), will be from internal abrasion- friction from the fibers working back and forth at several thousand times a second.

I hope he decides to take it forward, as it's an excellent subject, and he does his videos well.  I love the builds on some of his tools, I wish MY shop had a perfect spot for an orphaned waterjet!

I am now buying the straps with a section of chain at the hooks. I find them much better when trying to attach to stake pockets or rub rails.

Sometimes, especially for tractors, chain is still the best.

The guy did a great job showing that a couple twists do nothing to hurt the load... and yes, they will stop vibration from the wind "whipping"..

Knots and sharp edges are all you have to worry about.