1. for all I know no use, just bragging rights and... fun. :)
2. I wonder how many of achievements DLC spammers did because their excuse is needing more things, they probably did everything
EDIT:
So... I'll call you, which is hidden achievement, done.
Now all my sims have steel bladder so it is supposed to be tricky, right? Wrong!
Steel blader won't help your sim if he's drinking much.
So, set a bar in your home, remove toilet seats, mix drinks and use them till your sim's bladder go red.
Set a date, the place - your home.
Continue to drink at your bar, in a minute or so yor poor sim will pee himself/herself. :)
http://s29.postimg.org/vm9kcjwwn/call1.jpg
Also when I'm on dating again, did Speed Dating too.
Easy as pie after you grab Serial Romantic aspiration reward trait (no jealousy!).
Add three new random sims in your household through manage household (suggested trait romantic on all three), set your sim a date in sim's house with any of them and go first kissing before the time is up! :D
http://s16.postimg.org/utp2oq2ed/double.jpg
But there is another thing I can do on a date, and I did it. On a whim achievement. No philosophy, just set a date in the house and do whims that appear.
http://s16.postimg.org/4nki0byqt/whim.jpg