Let me start,
This feeds and readers and RSS news where very popular back in 2000-2010.
And somewhere in between that years illegal stuff happen, scrapers hit hard and now there are maybe zillions of ways to steal your content trough FEED, bomb your server trough FEED...
Advantage of having feeds:
1. your visitors can read your content trough RSS readers ( i dont know if this is advantage or disadvantage, sounds more like a disadvantage to me)
2. You will get more visitors (yes, that is true)
3. RSS readers can give you backlinks (but now with google backlink policy i doubt you want to have so many backlinks from god knows what places)
Advantage of not using feed and disabling it:
1. Faster server - scrapers will not be able to bomb you (if you have dedicated or VPS go check your apache log access and you can see get FEED spammers.
2. WordPress will use less resources, less memory and CPU. If you google WOrdpress problems you will see it is mostly memory and CPU problems and it looks like it is well conected to this flooders that bomb your feeds
3. Little harder to steal your content, no duplicate content , no google penalty
Now if you put everything on the scale i think disabling it forever makes sense.
I hope WordPress realize this and disable it or give us at elast option to disable it by our self or to make noobie wordpress users happy, disable FEEDS by default and give option for turning it on. But by reading this topic i dont knwo who will turn them on...
I will disable my FEED on all wordpress blogs.