[Serusers] newbie radius questions

[Klaus Darilion]

Hi!

After using radius for the first time, I came up with several questions 
about "why and how" to use radius. Please comment my questions:

As in the tutorial, I used freeradius and put the SIP users into the 
raddb/users file. Do I have to make this manually for every user or are 
there any tools do to this? Can radius be used with a backend database 
for storing user data? If yes, why not directly use the database without 
radius?

Using mysql for user authentication, adding new user is simple - serctl 
or serweb. I miss such a simple solution for radius.

Can/will radius also be used for location contacts - or is it a must to 
use mysql(postgres) for persistent user location?

Is there any functionality within ser+radius that can't be done with 
ser+mysql?

The only point I see for using radius is that many PSTN-gateways support 
writing CDRs into radius and billing systems will query these CDRs - but 
why use radius for ser?

thanks
klaus