At the end of the day, it doesn't pay to build anything, no matter how cool it seems or how 'right' you feel, unless it's backed up by numbers. If you do not keep goals and metrics in mind, development becomes an endless cycle of aimless iterations and your team's efforts are expended on trifles. What you launch will be disconnected from everything else. The goals of the business will not be met. You have to prioritize. This is how we do it.