“In theory, theory always works; in practice, it doesn’t.”
There are a lot of tires you can do this with, but there are definitely a lot of tires you can’t. It depends on the specs of the specific tire and rim as to whether it’s plausible. But it’s a good technique to know in any case.
When it comes to my MUni, with its 24" Sun Doublewide rim, I usually rely on the bike shop to get tires on. Off is easier, but the last time I put on a new tire, it took two guys and nearly 20 minutes to get the beast on there.
Also with my Coker with the Aero rim, tires go on really tight. It makes me smile to know I can get it mounted for the same price the bike shop would charge for one of those no-tools installations for an ordinary customer.
Most tires I can do myself, often without tools. I think it helps a lot if those tires have thin sidewalls or are generally thin.
I only watched to the point he got the tyre off, but he’s actually missing one important point in that video. In order to create the most slack you have to remove the bead at the valve - because at that point it’s impossible to get the bead to drop into the well of the rim as the valve stem is in the way, so if you try removing the bead anywhere else you will have less slack.
I can get almost all my tyres off and back on without tools - though it’s worth pointing out that my road tyres are amongst the easiest, so it’s not like he’s making things difficult for himself in that video. There are some it still doesn’t work with - the most recent I’ve had to use tools with being 19" trials tyres with a wire bead.
The most difficult for me are my 18" trike wheels. They are 1.35 wire beaded “schwalbe marathon plus” on a narrow V aero rim. There is just (almost) no room to get the tools under. Also, I worry about damaging the beading.
The hands only method saved the day for me. After a couple of attempts I now find it quick and easy. It also goes back on the same method.