we leverage serverless and s3 based architecture for much lower costs. However, it's applies for any application, not just for serverless applications.
Your costs and deployment pattern are your problem, customers don’t care about them.
Saying it is serverless means nothing to customers unless the serverless aspect applies to them, which in this case it doesn’t. If you’re only selling access to your product for a fee, then whether it’s serverless or not, customers couldn’t care less.
We actually started with "reduce your costs by 3-10x with infinite scalability" without talking about storing in s3 and serverless (along the lines of your thinking - only talk about benefits + what you do). But our users, engineers by their very nature, were skeptical about how Oodle works, so we ended up settling on a combination of why, what and how. This resonated better with our early customers and prospects.