If you’re a startup, you’re up against organizations with experience and capital. Your ability to pivot quickly (i.e. agility) is your survival. The “lean startup” approach is essentially scrum for startups.
Many startups go fast and hard, but lack discipline or methods for getting quick and early validation of the direction they’re headed. Although startups are naturally agile (e.g. smaller teams, less red tape, lower resistance to change, lighter documentation overhead, etc.), this isn’t enough. Stable strategy for turning learning into competitive advantage through flexible tactics drives innovation.