Yes. You will need an App to conduct commercial behaviors, e.g. E-commerce, CRM, after-sale service, etc. but your users don’t have to manually run it.
iOS provides a large system-level support, and can automatically wake up corresponding Apps when entering an iBeacon environment. Services such as greetings are automatically sent out without users’ interaction. Plus, many iOS systems such as Passbook also support iBeacon. The above functions also apply on Android similarly.