And besides, the majority of the Scizor are banded, or IIRC. A Banded BP only 4HKOs Max Def/HP Hippo, and can 3HKO the same Scizor with EQ. The main thing that Hippo has over banded Scizor is the ability to use a recovery move. In a 1v1 situation, Hippo can beat Scizor with just Slack Off/Earthquake. Out of 1v1, a U-Turn doesn't really do much to Hippo, it also 4HKO. Hippo can even take a CC from Banded Terra and EQ it back.
Hippo works best with hazards IMO. You can constantly whirl stuff out, like an incoming Keldeo to a Scizor. Or a Latias to a Garchomp. Its definitely not the attacker like T-tar, but it can still work pretty well, especially with spikes and rocks.