I miss this feature too. I think it is based on a wrong assumption: a user that visits the forum once already knows what happened on the forum in the past 7 days, and that’s why they don’t need a weekly summary.
On the other hand, the automatic and personalized composition is so good (and without needing AI resources) that it’s a pity that the occasional and regular users are not receiving it. Unless you are among the 5% of users that follow pretty much everything, the weekly summary will be still relevant to you. And if you think it’s not, you can tweak your preferences to taste.
As an admin, I’m convinced my users would know better what is going on in our forum, and would check more content fresh and interesting that they would like and reply more, which in turn would result in better curated content in our main page, which uses Hot by default. Think of it, Hot main page + Weekly Digest are made for each other.
As a user, true story: I used to be very active in another forum but time is limited so I decided to let it go. Now I find myself NOT visiting the forum for just a casual check, so that I will get the digest and concentrate my browsing and participation in a weekly session. Crazy, I know, but the digest has the time to curate cool & new, and I don’t.