Not agreeing with the comments that Souichi is "better" or more "interesting" than Hirota. Especially in regards to the argument that Hirota is just a "1D character going mad over jealousy" (Souichi was the same w/ Miwako); they've just flipped roles now with Hirota losing his humanity and becoming attracted to Miwako while Souichi (re)gains his humanity and becomes attracted to Chika. I think they're both interesting characters and I'd like to see where this goes for both of them.
Seems like Miwako values Hirota more as a familiar because he, as she said, has a lot more (humanity) to lose since he's had a relatively decent life compared to Souichi who's seemingly had it shitty from the start. And the more humanity he loses, the stronger and more useful he can be as a familiar. If there's a parallel to be made—I think Hirota would be the Seidou Takizawa of this series, but Seidou was considered a "failure" by the person who "turned" him, and for Hirota to be a failure in this case would probably mean regaining his humanity, but this is a tragedy so I don't see the same outcome for Hirota.
anyways miwako is hot as hell