Edit: An update has been added down at the bottom
Back in another geological epoch (about 40 years ago or so), I worked for an outfit called “Dër Ratskeller Pizza Shoppe.” That’s right, “Dër.” When the time came to build a second shop, I helped in the process and ended up as the assistant manager there. During the course of construction, I mentioned to the owners that “ë” only exists in Albanian, Kashubian, and a few other esoteric places for phonetic disambiguation (like the archaic English form reëntry, or the French noël), and that “dër” is decidedly not German. My input was ignored.

First of all, you may rightly inquire why pizza is being served by a sprightly lad in Lederhosen. Well, the original shop served beer on tap (a rarity in Salt Lake City in the 70’s) and so the concept of a Ratskeller made sense… and they happened to serve pizza as well. Dang good pizza, too – but that’s another story.
I guess they thought that adding those two little dots would make the name look more German to the untutored public, and – looking back at it – that may have been the case, because now you see them everywhere. Madison Avenue, in a mad rush to give foreign panache to their products, appears to have gone crazy for European accents.
On a recent trip to Florida, I happened across these examples in the brief space of a week; I have no doubt that were I to scan the aisles of any reputable grocery store or supermarket, I would see many, many more.


This stuff looks more like a can of Raid™



This one uses the “é”, which does not appear in the Italian word “due” (two).

The grand-daddy of them all. How is this supposed to be pronounced, really?
Americans tend to ignore the umlauts and other accents, pronounce the words as though they weren’t there, and toddle blithely along their monolingual way. But friends of mine from the Teutonic or Scandinavian countries, without the benefit of television commercials, would say these names in ways that might make them unrecognizable; good thing they don’t count. (Just kidding, folks, just kidding.)
It’s the fad of the moment. How long it will last, whether it has hit its peak, and what the next spate of nonsense will bring, no one knows. All I do know is that if I ever open a Pån-Ëurøpëan Яešţaüranŧ, I have just as much chance of succeeding as Joe’s Grill.
Edit: Only in the wee hours of February 2021 was I made aware of the concept of the “Metal Umlaut” or “röck döts” – heavy metal not being among my preferred music choices I had no idea this was such a common occurrence in the music world to have become worthy of a Wikipedia article.
The Old Wolf has spoken.
Coming soon: Thë Rêstäúråñt ät thé Ëñd øf thê Älphâbët.
Just for reference, no Pan-galactic Gargleblasters will be served in Utah.