Why focus on features isn't advisable?

Source: Allen Holub

Thinking in terms of features is a disaster. The main problem is that there is no direct connection between the feature and the user's actual work. Features describe your work, not your customer's. 

Many orgs chase one worthless feature after another, never delivering anything of value, and then go belly up. Even the MMF is a flawed notion. You need to release long before an MMF could be implemented to get necessary feedback.

Instead of features, implementing user stories does focus on the user's work, making it possible to do that work in a system that is far from feature complete. That provides real value, and it is often a salable product. Even if you can't sell it, you can get immediate feedback.