This!
This has to be the main selling point.
The second would be to NOT use a web service but to run your own desktop feed aggregator. Everyone should stop using walled gardens for things you can easily do yourself:
YOU should be responsible for what you publish - no one else.
YOU should be responsible for what you read - no one else.
It doesn't work any other way. I'm not able to decide what you can and cant write on your blog. I'm also not able to decide what you can and cant read.
If your crap ends up on my webserver in whatever way I will be responsible for it(!)
Someone once said: When you grow up you have to be your own mum. It might sound like a lame joke but if you want lame nothing can beat a formula where one ends up responsible for what other people publish. Any amount of needless centralization will have the usual suspects pressure that entity into censorship.
What is legal in one country will land you in prison in the next.
Employers, government, border and airport security etc cant "ask" you for access to your home desktop computer.
But more importantly: Without RSS you cant read small websites that rarely publish. This also means you don't have to make your own website anymore in 2018 because no one reads it.