5. Why do I need a hotspot for public internet access? I already have a traditional Wi-Fi network

A traditional network is used to share computer resources configured to be part of it, in a stable manner.

A hotspot allows you to give temporary access to your network to users outside your organization, with their devices (notebooks, tablets, smartphones, etc.) without having to change their configuration. It also allows traffic management, authorization profiles, filters and much more for your security.