It can be used to boast
If you use your status to boast about all the cool things you are doing on a day to day basis, then you will be de-friended. It's the British way – nobody likes a boaster and nobody likes that you are having such an awesome time all of the time.
With Places it means that you aren't actually doing the boasting, the service does it for you.
So if you happen to be in Kenya one week, Tokyo the next and up the Eiffel Tower the week after, Places will let your network know.
It'll kick-start your social life / stop you missing out
There's nothing worse than peer pressure making you do things, but at least it gets you out of the house. Facebook Places will let you know just what you are missing out on when you say no to an event, even though you are free to go to it.
Once you see updates of all your mates going to your favourite bar, then you will probably end up going along, which isn't exactly a bad thing.
Facebook Places certainly isn't for everyone. If you just use Facebook to laugh at what your 'friends' from school have done with their life, then you will have no use in finding out who is where and when.
But Facebook is a social network and for those who want to be social then it does open up the possibility of meeting your friend group face to face and not through a computer.