Although I agree with the author of this article that the terms are somewhat muddied, even in their more generally accepted definitions, by the fact that it's hard to draw the line for when unlockables can be considered "permanent progression".

Although I have many gripes with the terms in general and how they're used, I'm of the opinion that it is clear enough for there to be a distinction; if all of the unlockables in a roguelike game are sidegrades, or merely more options without inherent strength over other options that are unlocked from the start, then it still counts as a roguelike.

Though admittedly, this can be a bit blurry too.. it would be pretty easy to argue that some unlockables in games like these are more powerful than other options, especially because it's very hard to put an objective "power level" on an item in a roguelike. Also, one could argue that merely having more options makes the game easier, thus it counts as permanent upward progression.

Yet regardless, the article's attempt to coin the term "rogues" as the all-encompassing sub-genre/game mechanic name absolutely won't catch on, and the differentiation between the terms does have a lot of value for people trying to determine whether or not they will enjoy a particular game, even if the line can be a little blurry.

Here's a relevant video that I enjoyed by Game Maker's Toolkit that focuses on the main mechanical differences between the two designs, from a very broad and practical overview, definitely recommend watching it if you're interested in this sort of thing

https://www.youtube.com/watch?v=G9FB5R4wVno

Here's another tangentially related video by Chariot Rider about roguelike progression in particular, which I also found interesting, although less relevant to this discussion

https://www.youtube.com/watch?v=yOfgUFx9RkU

Even more tangentially, here's a fun video by Lextorias about confusing or controversial game genres (well.. game genres in general) and it has a big section about the distinction between roguelikes and roguelites

https://www.youtube.com/watch?v=5zrxN3_JHy0