Comment by thaumasiotes

> The purposes you mention are much more easily achieved by being simple to draw.

No, that is not true for either purpose. Being simple to draw is a negative in both cases:

(1) Things that are simple to draw can be easy to recognize, but things that are complex are easier to recognize.

(2) Things that are simple to draw are never visually impressive.

And the flags that are easy to draw are so simple that it's interfering with the ability to recognize them. The first example there would be Ireland vs the Ivory Coast:

https://en.wikipedia.org/wiki/Flag_of_Ireland

https://en.wikipedia.org/wiki/Flag_of_Ivory_Coast

Another common confusion is Russia vs France, though in that case someone who needs to be able to tell the difference won't have trouble:

https://en.wikipedia.org/wiki/Flag_of_Russia

https://en.wikipedia.org/wiki/Flag_of_France

> For a similar case, see the flag of Germany[1], Austria[2], Peru[3], Finland[4], Italy[5], and need I go on?

Go on? Try beginning first. Every single one of those links presents the flag without the coat of arms as a default and the flag with the coat of arms as a special case.