Black Beast carries his power (enough at least to get tired opponents out of there) very well. And equally as importantly doesn't quit fighting in fights that he's losing. He's shown it multiple times, it's a pattern.
I like Ngannou to get the early finish as I think Lewis is just way too open to getting hit early in fights and even if you think Ngannou's power is a bit overrated (I don't but whatever) it's still obvious he's one of the bigger punchers in MMA. But IF Lewis survives, he may be an amazing live bet at huge odds if Francis tees off on him early.