1. They have more user trust. People who join and stick with Foursquare, GoWalla, Whrrl, etc. trust them. Facebook users are not clamoring to have their Facebook account show their "friends" where they are at any given moment.The majority of Facebook's core users probably won't want it, like it or use it. Or more likely won't understand it and won't realize it is on their account or will have something go wrong because it is. Sure, some will use it, I'm not denying that. But I don't think it will be because people trust Facebook, and I anticipate a fall out.
2. They are focused on doing one thing well. Foursquare, GoWalla, Whrrl and the like do what they do well and keep getting better at it. Facebook is going to collapse under it's own weight at some point and is already succumbing to feature-creep because they are getting paranoid about holding their position. Feature-creep, of course, is only one of Facebook's problems that they're a bit too arrogant to see (privacy anyone?). Having the Places feature on Facebook isn't going to keep people from joining and using other, better location-based apps.
3. They already have my "trusted friends" list for location announcements. I will still use Foursquare or GoWalla and not Facebook's places because I've already put together a thoughtful list of friends and acquaintances with whom I will connect and allow them to see where I am at any given moment. If I want to create a photo-based, location-stamped experience, hands down Whrrl is my favorite app. I don't feel the need to give up any of those apps because now Facebook has added Places. I don't even use "Broadcast to Facebook" feature on any of those sites on a regular basis.
4. They are nimble and present. The smaller guys have an advantage over the gorilla in the marketplace. You can't move as quickly or respond as immediately as the smaller guys. I have had major problems with Facebook and have tried to contact Facebook for help. Last year, I ended up with someone who lacked any of the skills or information needed to help me. Remember my post "Is Facebook Tech Support Human?" More recently, I received no responses at all to many, many submitted requests including when I was asked by a friend to help get a profile removed from a relative who had killed his wife and father-in-law than committed suicide. Surely Facebook could have at least responded to our emails for that, but no, nothing. Someday Foursquare, GoWalla and Whrrl will be so big as well, but right now they are incredibly responsive, enthusiastic and able to offer actual customer service.
Yes, Facebook is Big. Yes, Facebook is Powerful. But size and power doesn't necessarily translate to always being right or making good decisions. Deploying Places on Facebook is not a big deal other than it does show that the "little guys" were smarter and more creative innovators than Facebook.
I'm not buying that Places on Facebook, however, is a good thing. Are you?