I guess in the long term the product will at least pay for itself, in the short term it will just be a marketing campaign and gives people a good reason to switch from their Amazon stack in case they don't depend on things like EC2-S3 transfers. When comparing to Backblaze B2 [1], Cloudflare's storage cost is 3x but you don't pay for egress as a tradeoff (compared to 0.01$/GB for Backblaze).
[1] https://www.backblaze.com/b2/cloud-storage-pricing.html