Whatever the case, I am so glad that Robin's moveset has the spells from Fire Emblem, with his sword kind of being implied as his fallback weapon, rather than the main one. I've always been more of a magic person when it comes to JRPGs and Fire Emblem is no different. And since I've always played my Avatar as being a magic person (he was a Sorcerer, if you want to know), I like how he even gets to use dark magic as well.
Incidentally, I don't think anyone's going to be surprised at what I'm saying next, but Robin appears to prefer the lightning element, which is a nice callback to how your Avatar starts out with a Thunder tome and uses thunder magic in cutscenes.