Strictly speaking, all English nouns have multiple cases. The others just happen to look identical to the nominative form.
I disagree. It depends on your analytical perspective. Certainly the pronouns have three cases (he / his / him), and some of the historical cases survive vestigially, but noting that the current nominative case has absorbed the other cases isn’t the same as saying those cases are still there.
I think that Latin as it’s usually taught is more useful for understanding how English works than English as it’s usually taught, but that’s because any course in Latin is at least half a course in linguistics in general. I imagine you could get at least as much out of a course in linguistics which used English as its model language, except for some reason that’s seldom done.
After thinking about it a while, I’ve concluded that my post above might be the most obscure joke I’ve ever made.
And to try to stay on track, I took Latin in high school, private Catholic HS, in the 1990s.