Why is region restriction so 'restricted'?

Currently you can select a region in which your giveaway will be restricted to, because the game itself might also be restricted to that region.
But the different regions you can select are very limited, and you can only select up to one. And this is slightly inconvenient because some games are restricted to multiple of these regions or, more often, instead banned and restricted from a only a few of these regions.

Not many people use region restrictions, neither do I, but i suggest adding more selectable regions would be an improvement for the ones that use it.
And yes, there was a similar but small thread about this many months ago, though I am not into necroposting so I made this new thread.