Both have questionable defenses. Both can put up a lot of points.
I'm not sure why the Rams are currently 1 point favorites.
I see this game as a toss up. I will say that the Rams play awfully well on the road, so that might the rationale.

But, they have been well prepped by playing Wilson and the Seahawks this week, in the sense that the Rams have just played a super mobile QB with a great arm. The difference is that while he's slippery and quick Mahomes isn't that fast (in fact, I think he's about the same speed as Goff in the 40). Wilson is RB fast, which makes him all the more difficult to defend.