Did quotation marks have other applications or uses, like for emphasis?

I have frequently observed instances of quotation marks being used in interesting ways, often with rather funny implications.

Here are some notable examples of unnecessary or suspicious quotation marks:

The "Blog" of "Unnecessary" Quotation Marks has many other examples. Examples I’ve seen in my everyday life are not as funny as these examples, indicating that it’s not just meta usage intended to be funny.

My question: Was using quotation marks for emphasis ever taught as a standard application of this punctuation mark?

While the examples I’ve included are modern, I’ve anecdotally noticed that older signs more frequently employ quotation marks for emphasis. (My great-grandfather was a sign painter, so this may just be my own bias towards noticing older signage.) Similarly, I’ve observed that in online/text communication, older people are more likely to use quotation marks in this manner (in the same fashion as the infamous overuse of ellipses…).

I wonder if 1) usage has shifted over time, 2) these are ‘valid’* albeit uncommon applications of quotation marks, and/or 3) this usage isn’t so common as to become a widely accepted application (hence why they’re funny).

*Valid as in common enough to be considered an appropriate application of the punctuation. I don’t mean valid as in the High and Mighty Arbiters of the English Language have prescribed it as correct and acceptable.