The anime had almost nothing to do with the manga, but yet the OVA follows the manga exactly.
If you've seen the anime, you should still watch the OVA. OVA 1 and 2 match the anime, but from then on it's a completely different story and hell of a lot more interesting.
And really, the anime just plain got the CHARACTERS wrong. Alucard is a sadistic evil monster. Seras is capable of being a badass bitch. The anime made Alucard and Seras look like pussies in comparison to their manga/OVA originals.
So yes there's a point. WATCH IT