Comment 8 for bug 895535

Of course that would work, but it still would need me to go through the list and add numbers, which is plain annoying work (especially for building types).

This iterator just makes your life easier, you don't have to worry about copy and pasting around anymore, reordering lists, whatever. Of course, if you throw it around several included ini files, it will break list orders, but that's a problem with inclusion already.
Still, it is the modder's choice whether he wants to use this feature or not, I know I do.

It also follows the INI "syntax" (unlike your simple list idea without any '=' characters), and, thanks to the choice of '+', actually looks like an addition.