Only if you never, ever have to deal with shitty websites from countries that pretend the rest of the world doesn’t exist. Looking at you, FUCKING DELL HOW CAN YOU FUCK THIS UP YOU ARE A MULTI-BILLION INTERNATIONAL CORPORATION
Oh, like IKEA naming things in Swedish (like söderhamn, soederhamn if you want to try and pronounce it)? I love those it's so funny too here people try and pronounce the names.
But that's just how it's supposed to be written if ä, ö, ü can't be used. And since URLS don't accept them, they get changed to ae, oe, ue. In crossword puzzles you also have to write them with the e
I can only speak for French. It's a whole letter representing a vowel called "l'e dans l'o" (the e in the o). It's completely different from an accent and doesn't work according to the same rules as accents. I know it may sound crazy but yes, there are rules/a history for diacritics in French, and that letter is not part of it.
It does make two different sounds depending on the word though, so maybe œ should get an accent?!
There are a lot of languages with lot more goofier letters. Catalan has Ŀ to distinguish two L's and one ll. Hungarian has long Ö and Ü which is Ő and Ű. Irish has letters the letters Ḃ, Ċ, Ḋ, Ḟ, Ġ, Ṁ, Ṗ, Ṡ and Ṫ. You could also count the norwegian and danish ø but thats a pretty normal one. Theres probably a million more but these are the ones i have experience with.
Yep, the onces here are just the languages I kind of speak a little bit. Apart from those my absolute favourite is the Maltese character Ħ, or as I would call it; a road block.