I don't necessarily agree with that. We're talking about supernatural beings to begin with. Maybe their main ability is said "youjutsu" or "hijutsu" and, of course, that'll be their main thing. However, that doesn't specifically rule out that they can use magic/mahou. Of course, they won't be able to use it as proficiently or as advanced as a Magician. And the best exemple for that are tengus and I always seen danmaku as magic. Additionally, there's no way that youkai with symbolic abilities such as Remilia's or, one of the subject matter, Hecatia can't use magic in one way or another. I wouldn't be able to see them as high on the "food chain" if they didn't one way or another.
You've completely misinterpreted what I meant. Everyone can obviously use supernatural abilities which we might as well call "magic". That's a perfectly acceptable translation of "youjutsu", which by the way
never shows up as their "main thing." It's only used more casually, in descriptions like "Suika is better at youjutsu, but Yuugi is physically stronger." But what magicians use is something more specific than that. Maybe you could think of it as "sorcery" or "spellcraft" or whatever. It's a
category of youjutsu that's specific only to magicians. And in Japanese it happens to use the word "mahou" which is a much more common word for "magic", which is why we translate it as magic.
The point though was just that the word used in Marisa's profile is only ever used to describe what magicians do, and is used in the profile of every single Magician in the series, from Alice to Byakuren to Narumi. Every single one of them has "the power to use mahou (specializing in X)" as their ability.