I like his videos but this didn't really break any new ground. You buy the expensive carbide tipped blades if you have very hard (metal) material to cut through. Similarly you don't buy a drill set that's carbide if not drilling rock or cobalt if not hard metal, if you're only drilling wood and other soft materials.
Then there's the thickness. You get demolition blades if your saw has enough muscle to use them, but you get thin kerf if you need to get into angles where the blade flexes, or if you have a weak cordless where the thinner cut width spares the battery.