This seems great in theory but unlikely to work well in practice.

Your close friends are already in touch routinely via email, phone, text, in person.

Your extended network of acquaintances though? Connecting on a social media site is much less of a hurdle than: make them aware you have a newsletter. Get them to click and subscribe to the newsletter, get their email client to route that newsletter to their actual inbox so they see it, etc.

A newsletter seems best suited to those with a bit of fame, enough to have a bunch of 'followers' - who will seek out and subscribe to a newsletter.