As something whose value is focused solely on reducing the cost of SMS OTP, without a net increase in security assurance, which shifts the compromise risk into

As something whose value is focused solely on reducing the cost of SMS OTP, without a net increase in security assurance, which shifts the compromise risk into another threat (from sim swap to malware), aimed at developers who aren't equipped to reason about security and people who are sensitive to SMS fees, it's a narrow solution that could be one of those, "it shouldn't work but it does," things (like mPesa). Your risk will come from security people in enterprises who know this stuff and will hamper and derail your sales. The opportunity will be in small app developers who get sudden traction, and relying parties will accept the risks of the authn method in exchange for access to that user channel. I can see why someone would take the chance on investing in someone building rope bridges in developing countries, where engineers would say it's wrong for every conceivable reason, but someone is going to own those routes whether the bridges are rope or steel suspension and there is first mover advantage. As you can see, security people will likely not be your allies in this, which is fine, but that's the heads up. Presuming you have a channel to those developers in 3rd world markets, I could see how YC might want exposure. If nothing else, it's a case study and a useful example of how VCs see risk vs. how engineers see risk.:) Good luck!