Just knowing how to tie bowline, double bowline and a few hitches will make you a more useful person.
It was surprisingly helpful - I can't even remember where/when I learned them.
As he says on the site, you wind up with the same knot (slipped square) that you'd get by the usual method of tying.
The bowline rules for tying one-handed. Otherwise, I'm inclined to agree with you, but properly dressing the figure-eight can be bit of a chore. It's too easy to get the ropes crossed inside the knot. For non-climbing use, I like the alpine butterfly family. Strong, versatile, and easy to tie in single, double, or triple-loop versions.
Personally I use a bowline + stopper for climbing, figure 8s are a swine to undo with pumped arms if you fall on them hard & if you're pulling the rope through gear there's always the worry you won't fully untie knot.