Why was https://security.stackexchange.com/q/88834/at-what-point-can-you-you-implement-crypto-algorithms migrated to Cryptography Stack Exchange?
From my perspective as a Security.SE user, this question is on-topic. It's about risk management: deciding when you should roll your own crypto implementation vs using someone else's. I could understand that the question could be considered too broad, but I don't see how it's off-topic in any way. Cryptography is directly relevant to security, and managing risk is the job of a security professional.
From my perspective as a Crypto.SE user, this question is unanswerable — fitting under both primarily opinion-based and off-topic. It isn't about cryptography itself, but about deciding how to go about using it, which is off-topic — it fits the close reason “Questions about security policies that may be based on cryptography (as opposed to the design of cryptographic algorithms and protocols) are off-topic here, but may be asked on Security”. Inasmuch as cryptography is concerned, the only Crypto.SE answer is “if you feel like it”.
As I had written before, I had to vote to close the question on Crypto.SE once it was migrated. The question is now undergoing a contested close review. Migrating questions back and forth isn't good experience, and migrating questions to a site where it isn't even answerable is definitely not good.
