It's for private photo sharing with family or close friends. It's more like an open-source, self-hostable TinyBeans or PhotoCircle. I explain the motivation more in the design doc:
https://refactoringenglish.com/excerpts/write-an-effective-d...
https://refactoringenglish.com/excerpts/write-an-effective-d...
You could approximate it with email, but I want things that you can't do with email like letting recipients control the frequency of emails, making high-res images available without bloating everyone's inboxes.