I also have a slightly different take on this, having used email newsletters and email marketing (Yes, they are different things) for a little over 4 years now.

A newsletter is to keep in touch with your ideal readers; a marketing list is for you to curate and get your ideal clients.

In fact, I don't even offer an opt-in or a lead magnet anymore as part of my sign up. With my newsletters, it's a very 'what you see is what you get' approach. It's worked splendidly.

As of two days ago, I've cut out all social media from my business model (except for LinkedIn, which I use for networking with business peers). The email list is my favourite place and always will be. :)