There's nothing wrong with those options either. But some problems are opinionated or not specific enough for Stack Overflow (e.g. "what are the alternatives to include comments on a static site"). There's also the certainty that my content remains independent from other platforms and it remains available online as long as I keep paying for my server + domain.
Not the OP, but the reason that I don't use those platforms is, essentially, control. I don't trust any of them to exist forever, or to continue to operate in a way that works for me.
Keeping everything on a site that I am in control of eliminates the issues of uncertainty.
(I do answer direct questions on Stack Overflow and such, I just don't keep my accumulated works or investigative notes on third party sites.)
