The digest/summary function is pretty different under the hood from a newsletter, though. It’s not sent to everyone at a specific time – it’s individually created and sent to each user, based on the interval set in their preferences, and only if they don’t visit the forum in that time.
I’d imagine you’d want a curated newsletter to go out to everybody, with the same content, at the same time – not in a week or a month or whatever the user has selected (or not be sent at all, if the user visits the site frequently.)
A couple of options you could look at, if you haven’t already:
- hooking users into a Mailchimp list with Discourse Newsletter Integration - Plugin
- creating a newsletter topic within the forum: A curated weekly newsletter for your community