Hello guys, I need your advice!
What is the difference between a hotspot with radius server and without one ? it really confuses me.

This is how I normally create a hotspot server:
Step 1: Add a new network
ip -> addresses -> add
Step 2: Setup DHCP server
ip -> DHCP server - DHCP - DHCP Setup
Step 3: Setup Hotspot server
ip -> hotspot -> hotspot setup
And Done!

I'm using this method for half a year now and it's working great. But why some other people use radius server for their hotspot?
And also, what are the advantages if you use userman to create a hotspot server?

For one thing, a separate Radius server allows you to use an online billing service other than the one or two that ROS supports.

Also you open users in radius not in Mikrotik, and you will have an accounting history in radius!