Skill Bonus
"I wonder about its applicability to other skills..."
That might be an idea for a new topic.
It seems funny to use a skill roll to get levels with another skill, though. But limitations like Side Effects, Incantations, Gestures, Visible, and certain Conditional limitations, can give these extra skill levels the "flavor" of simple magical charms. Also consider if such levels are subject to magick Detect, Dispel, Suppress, etc.
For example, Crocodile Dundee has a big bonus to his Animal Handler roll with gestures (hold out one hand with thumb and small finger extended) incantations (if you want to consider that sound he makes an incantation) a limited number of things he can get an animal to do (perhaps "don't attack me" but not "go attack that guy") and any shaman in the vicinity can detect what he's doing by making a PS: Shaman roll with perception modifiers (okay, I don't remember that from the movie and I'm just making that one up.)
Yes, Lucius Alexander is back
And so is the palindromedary