Website impersonation just happens to be one of the techniques.
I guess. If we were going off your definition, then the site could certainly be classified as a phishing site given that it's obviously trying to maliciously obtain the private keys of the users.
But they might not actually trying to impersonate anyone's site in particular as you say, since the closest thing I saw to their project is probably Agrello, which was rebranded from delta, and this site currently looks absolutely nothing like what Agrello's site looks like or even the service that they provide.
At the end of the day though, this barely matters. They are a noob-targeting scam, no matter the classification.