If/when you debut the [robohash] watermark in the image, it would be great if you would also debut a paid plan without the watermark. Plus, paid plans give people confidence that your service will continue to exist.
It's not silly for people who are actually using this. I'd rather pay for the service than living with the uncertainty of getting a banner because you can't pay your CDN bills. That's really the only thing that prohibits me from using this service in anything useful anyway. It looks very nice so that clearly would be a waste.
