There will always be a subset of users whose goal is to not use your service, but to arbitrage your service into the maximum value for themselves. For example -- let's say you offer $100 in free AWS credits by signing up to your platform. Expect a malicious user to eventually come to your platform, realize they can resell those $100 in credits for $50, and start using your platform for their own gain. Unless the mech…
Bonus abuse is a small shop, whereas phishing through third-party services is much more likely to be an organized crime group.