This is a spacing and dodging test where Varus holds a massive range advantage. You win by surviving his poke and using E to dodge his critical crowd control, then running him down with R while he is immobile. Mid lane's shorter length means you have less room to chase him, so your timing on all-ins is everything.

This is a scaling battle between two high-mobility carries. Smolder wants to poke and stack P from a distance, while Zeri looks for a window to burst him down. You have more early kill pressure, but if Smolder hits his stack breakpoints, he will eventually outvalue you in teamfights.