To his credit, the presenter, after mentioning the buffer pedals he builds and sells, also acknowledges, among other things, how almost all Boss pedals come with their own built in, decent quality buffers. This is a practical tip for folks lacking a guitar with an on-board buffer but own one at least one Boss or another buffered floor pedal that they run first or early in their signal chain. (6:06 - 6:20 in the video).
I also really appreciate how the presenter ends his video by reminding us to, "Play guitar and have fun - don't obsess over these topics, especially these things like true bypass and buffers and what do you need ... Just remember, all of you are different, I'm different, it's all opinion-based on your ears and what you want out of your rig. That's why these things are impossible to find a good answer on forum [sic] because only you know what you want to hear. So I encourage you, just play guitar, do the test I asked you to do, take it from there, and be confident in what you have going on for yourself." (8:00-8:46 in the video)
For folks wishing a detailed electronics explanation of how buffers work, I like the video below too, you might also:
“[P]ersonally I disagree with the general philosophy of ‘genre equals gear’ at anything beyond a cosmetic level. I think the right idea is to find the right amp for you, and then play whatever kind of music you like. The “Jerry Thing” was just Jerry. It wouldn’t have mattered what he used and he used a lot of stuff.” Steve Kimock (The Gear Page 04/08/18)