about backup choices

I click the backup icons on CP. There r two choices.
1) full backup (but u can not restore it from CP?? r u kidding me, then what’s the point for this full backup.)

2) sepreate backup. including
a) home directory backup
b) DB backup
c) email forworder backup
d) email filter backup

I install WP just right under my home directory public_html.
If i choose 2a, that’s enough? coz wp-contents is under home directory as well. So I dont have to backup DB again. is it right?

In my opinion, DB only keeps your posts and comments, but those pix/videos are kept in wp-contents. I searched some articles that said you have to backup two things: DB and wp-contents.

Can anyone clear this? thx