Maybe... A company I used to work at has a really good adjacent network... I had suggested that they put more effort into their industry blog and newsletter instead of some of the other marketing ideas. Both are now a significant portion of their traction and a lot of people are there for the content. Marketing is just a side effect, even if the purpose of the content was marketing in the first place.
I mean, there are ways to do newsletters well. Articles from Tailscale get on HN often for example. I would agree that spammy emails are not helpful though.