But, I'll counterpoint that LetsEncrypt isn't the only ACME provider. Should they behave badly others can step into the gap.
The 90 day thing isn't a barrier. Certificates in general are automated- it's no harder to be HTTPS than HTTP.
Promoting HTTPS and dropping HTTP is ultimately valuable to all sites, because it prevents HTML injection. Given that your reader will be accessing the web via an ISP it prevents that ISP from injecting things into your site.
As an author of my own websites, I'm https only, and I think LE improves the indie web experience. There is a long chain of big companies between my site and my reader (Isp, LE, DNS, browser etc) but HTTPS offers me the best way of making sure the contect I create is the content delivered.