Where is everyone replying getting the idea that there are 2 different spell types
Because the lore of literally every single Divinity RPG says that is the case.
Source was different than regular magic in Divine Divinity, Divinity 2: Dragon Knight Saga, Divinity Original Sin 1, and Divinity: Original Sin 2, and in fact Divinity Original Sin 2 makes it clear that Source and magic are different.
In conclusion either you are an idiot or a troll, so I am done with this.