If asked to make icons for languages, whet else would you even use instead of flags? Icons help find things faster, and the users are used to seeing flags next to language labels. In some cases, a single flag indeed does not sufficiently describe an option. In this case, combine, like, two flags, e.g. (flag of Spain)(flag of Columbia), or invent some other clever icon to disambiguate selection.
> Icons help find things faster, [...] I _highly_ doubt that being able to input the name of the language (or country or whatever), both in its native and translated form, is slower than scrolling through all possible icons.
Here's a funny example of where flags are useful:
People from Slovenia [SI] (natively "Slovenija") speak Slovene/Slovenian [sl], natively "Slovenščina", ajdective "slovensko".
People from Slovakia [SK] (natively "Slovensko") speak Slovak [sk], natively "Slovenčina", adjective "slovensky".
Opening up a language picker, I usually search for "slo" (if there even is a search bar!) and then read the options left. But since the difference can be as little as a single character, even without dyslexia and with good eyesight, I still screw it up sometimes. The flags however, even when small and/or blurry, can still be quite easily differentiated by anyone familiar with both.