> I just follow them on Twitter and use Twitter as "RSS reader".

This quickly breaks down. I subscribe to 1096 sites according to Newsblur. I would 100% miss some content from those sites if I only followed them on twitter.

And for some of those sites, that's probably fine; a fair amount are just 'entertainment'. But there are updates I would hate to miss, even if they tweeted links to them at 3am or right before a huge tweet-storm from someone else.

That is exactly the problem RSS was designed to solve.