Session lib

[eluser]leonglass[/eluser]
I have a class that I have used before for managing sessions that makes use of phps session handling and using a db. I have been looking at CIs session class and have seen that the actual user data for the session is still stored in a cookie even when you set it to use the db. The class I have places the user data into a field in the db as name value pairs separated with semi-colons.

My questions are -
is the way CI does sessions better than the way I have been doing and if so why?
What do you all think of using my own class as a lib in CI does that make sense or not?

thanks