I think it’s just not implemented because the devs didn’t know it was an important feature to prioritize. It does supposed saved posts, which I imagine is what the devs anticipated was most useful for users.
Gotta keep in mind we’re just about to get 0.19.0, it’s not even v1 yet so a lot of things are still missing.
But yes the data exists, in fact I have the vote history of everyone my instance has seen in the communities I’m subscribed to.