This is interesting, however my main problem with really long Wi-Fi password are devices that have bad ways to input text. Things like media box using a remote controller or a video game console using it's controller.
WPS was born to fix this, however the specification is so broken that it is literally useless from a secure standpoint.
On some devices it may be easier to enter a long password from a restricted character set than to enter a shorter password from a richer set.
For example, I've seen TVs that allow using a numeric keypad on the remote for entering digits in text and password fields, and require use of a clumsy on-screen keyboard for entering letters or punctuation. The on-screen keyboard is navigated with the up/down/left/right/ENTER buttons on the remote, and might have multiple shift states for case and punctuation requiring navigating to and pressing a shift key whenever the password has adjacent characters that need different shift states.
On such a TV, I'd rather enter a 39 character all numeric password than a 22 character alphanumeric password. Entering 39 characters on a hardware numeric keypad is way faster and way less error prone.
if the on-screen keyboard even has all the characters needed.
when we got new internet in our previous home i was forced to change our password that everyone had already set from previous use, because the new configuration interface didn't allow spaces. so i used underscores. then family visited and they had a tablet with a keyboard that didn't have underscores.
Or when you setup a new apple computer, you have to enter the wifi password without being able to see what you type, without being sure it is the right casing, and if you are not in the US without being sure you are using the right keyboard layout in the first place (the is no opportunity to type something else in a clear text box before that step).
When a friend tried to connect to a new network on their MacBook, a second friend with an iPad got a pop-up that such-and-such was attempting to connect to their network, and if they wanted to share connection details. One click and they were in.
WPS was born to fix this, however the specification is so broken that it is literally useless from a secure standpoint.