See the newer version of this video on this channel which adds clarification and a better demo - "The Myth of SWR 2."
Clarification at 1:56 - Unless SWR levels are extreme with high loss coax.
The amount of misinformation about this topic, even among experienced ham radio operators, is staggering.
Here's a sample of what's coming which may make your head explode. This is from antenna engineer Walt Maxwell, W2DU.
"From the viewpoint
of amateur communications, it can be shown
mathematically and easily verified in practice that
the difference in power transferred through any
coaxial line with an SWR of 2 to 1 is imperceptible
compared to having a perfectly matched 1.0-to-1
termination, no matter what the length or
attenuation of the line, and that many typical
coaxial feed lines that we use in the hf bands with
an SWR of 3 or 4, and often as high as 5 to 1, have
an equally imperceptible difference."
See the references below. More ham radio "old wives tales" to come.
https://www.k3emd.com/downloads/Reflect.pdf
https://na0tc.org/lib/exe/fetch.php?media=technical:swr_and_reflected_power.pdf
http://zs6wr.co.za/documents/SWR.pdf
ARRL Antenna Book under "The Conjugate Matching Theorem"