I asked the youTube guy that and he thinks for home defense you'd want max spread since your range will be 15 yards or less. So, he advocates buckshot.
He obviously hasn't patterned his shotgun. At 15 yards buckshot isn't going to open up much with any normal choke/barrel. I use a rifled barrel and that will open it up a LITTLE more.
I see wax slugs as a way to really skimp or an emergency effort. If I needed absolutely all the defensive ammunition I could get and the shelves were empty I could convert my several hundred rounds of random sporting loads to wax slugs pretty easily. I might experiment with them in order to boost confidence in the item.
In any other situation I can load/buy something better, even if it is much more expensive.