It's an interesting point of view, conversely, as an Australian of some decades, they all look fairly normal to me and a subset of a greater spectrum I'm also familiar with.

Right angle plugs may well be less common (in your experience) but they're essential for, say, getting power from the wall to a breakout strip (for TV + games consoles, NAS, media box, etc. corners) when the wall plug is behind a low cabinet / cupboard.

In any case it's a museum, a catalog, intended to show a range of things that do exist, even if a good number may not encounter them frequently.