I recently jumped on making a rather long answer to this question: What is a Smart Card?, without asking myself: is it on-topic?
Also, my answer contains a lengthy historic/introductory part, with almost no crypto (the closest thing is a simple, interesting and still useful integrity check, but that's key-less); is that abusive?
It's borderline, but I think the question is on-topic here, and your answer is appropriate for the venue. Both the question and the answer would also be appropriate for [security.se].
On Crypto.SE, the thread is on-topic because it's about how a particular type of device implements some cryptographic primitives, what kind of security there is around this implementation, and what kind of use cases it's put to.
On Sec.SE, the thread would be on-topic because it's about how a component of some security infrastructure works, what kind of security properties it has, and what security infrastructures can use that component.
There's no “hard” content for Crypto.SE in the sense that there's no math, but what kind of uses crypto is put to is also relevant for this site. There is overlap between sites — Crypto.SE is a site about crypto, not a site about the part of crypto that Sec.SE doesn't cover. If it's strongly related to crypto, it's on-topic here.
