Which voters out there consider Attila the Hun to be a praiseworthy leader? Or Genghis Khan, for that matter? Intuitively it seems like the Roman Empire and Christendom would be more advantageous comparisons to make if you're dead set on appealing to conservative CK3 players for whatever reason.
I have a feeling a lot of people think Attila the Hun was a semi-mythical figure along the lines of King Arthur or Robin Hood, rather than an actual historical person whose existence and actions are well-attested.