Earlier quoted context omitted.
An option, strictly speaking, has an underlying security that already exists. The Safe, like a convertible note, doesn't have an underlying security yet, since the company hasn't created the preferred stock that it would convert into yet.
Well, sort of. In a broad sense an option is simply an irrevocable right to acquire or do something, without an obligation to actually acquire or do it. You can write options for whatever you'd like, despite securities being the most common use. You're right about securities; the security usually exists prior to offering a contract on it. But even then it gets a little more complicated. For instance, I can write a na…
But agreed, kudos to YC :)