I still think that the assumption is unfounded that every user who signs up to some message board is continuously interested in the activity there.
In fact I think that a lot of users sign up because they have some question and then maybe come back but many probably won’t (until they have another question). Certainly not weekly.
I think the default setting should be off; no weekly emails.
It’s odd to me that an open source tool used by many open source projects behaves like some startup trying to improve its “metrics”.