The point is to get features done, not tasks done

Yes, but hours aren't burndown. Accomplishments are. A team that focuses on hours isn't focusing on getting things done. Tracking hours makes it "OK" to do whatever you're doing so long as you're keeping the hours up to date.

The point of the Sprint or iteration is getting backlog items done, not getting tasks done. Tracking hours, in my experience, obfuscates that key fact.

-- Ron Jeffries on the Scrum Development mailing list