I would love it if a web wallet similar to coinos allowed me to give it a list of N preimages and have it create the next N lightning invoices using those preimages.

This would allow me to make a digital downloads store that has no backend logic. I could upload files to my server that are encrypted with a certain key, and then use the web wallet to sell users "secret" preimages which, when added to a corresponding "public" string, create the decryption key.

The logic could therefore all be done on the frontend: show the user an invoice, check if it is paid via the web wallet's api, get the preimage, construct the decryption key, and give the user their now-decrypted file.

Thus the server for a webstore could be a simple file storage system, such as Github Pages, and all the logic could be done on the the frontend, except for the delivery of the secret, which is done by the web wallet, in a way that the frontend can detect.