Small deployments stay genuinely simple. On a personal account you own your units, you get the alerts, and none of the organization machinery appears — no roles to configure, no territories to draw.
An organization exists when more than one person needs to be involved, and it brings the things that only make sense then: roles, territories, escalation between people, temporary coverage, and one shared view of the fleet.
It's the same product either way — the organization features are switched on by your plan, not a different application. Nothing you configure while small is thrown away when you grow.