yes I too have seen footers and calls to actions longer than posts, and I am not suggesting that. Do have a look at @leoplaw latest post and the call to action to sign up for the newsletter
https://steemit.com/dtube/@leoplaw/8vi4vwig

Mailchimps free features are rather impressive, and there is no way I would start to advocate people spending money to get them selves up and running. I have used mailchimp for a few years now, and I was able to keep under the limit for a good long time by cleaning down my list ever so often. If someone didnt open say the last 15 newsletters, then I would send them a mail asking them if they wanted to continue receiving mails, if they didnt reply, I would remove them from my list. No point in having dead weight.

What would you do if discord closed the door over night? Not saying this will happen, but reliance on a third party is dangerous. Steemit gets a lot of traffic, we know this because steemit inc are able to monitize it with ads now. there could be a lot of people that visit your blog once, like your content but never find it again. Giving them the ability to sign up to your newsletter gives you the opportunity to capture some of the traffic steemit.com gets.