I agree, the soldering techniques might not be the best ones. The first solder looks better than the "recommended" second one, then later I think I've spotted a cold joint, applying soldering to the tip might make sense only when desoldering, and so on, but anyways, the tricks shown in that channel seemed more practical than the usual life-hacks videos I've seen before, that's why I clicked subscribe, for the hacks, not for soldering advice.
About the copper wire as a soldering tip, in my experience plain copper was always better than any coated soldering tips. And they give peace of mind about not mixing Pb and Pb free, they don't need special re-tinning paste once in while, no need to religiously put fresh solder on a tip at the end of a soldering session, and so on.
- Particularly well suited for heavy soldering on big joints or ground planes.
- Could be used as an improvised micro soldering tip, too, by coiling a few turns of thin copper (AWG24, stripped from LAN cables) on a thick, plain-copper tip.
That's how I've soldered this:
without a $1k+ JBC micro soldering station.