Login using SU05 functions

I read some of the questions in this BSP forum regarding login functionality.

Is it too oldfashioned to use SU05 (internet user) functionalities in BSP?

Of course I must myself write the appropriate BAPI calls for checking, creating interner users. I think with SU05's BAPIs users could self-register themselves.

It would be nice if somebody could summarize the technologigal logon possibities in BSP scenarios. I have special interest in scenarios where no named SAP user is used in application login ( of course in the application service definition there is a dummy SAP named user ).