I think people can be romantic and still platonic. And I also think people can be romantic without sex. That's the difference between best friends and platonic. The romance. You don't need sex to feel some thing special, and that some thing special I would call romantic.

You can be romantic and platonic
but not best friends and romantic.

Platonic relationship must be some thing special or really what's the difference between best friends and platonic? I think imho it is the romance where we stumble because many people feel you need sexual attraction or sex for romance, I don't believe so.

Just my 2 cents