PPCGeeks - Navigation apps without ability to select from contacts

I'm curious...does anyone have any insight into why the feature that allows the user to select from his/her contacts from within the various navigation apps seems to come and go? I have noticed that Google Maps 4.1 no longer has this feature (I know 3.3 had it, but can't speak for others in between), and I know that Bing has also had it disappear (although it seems to be back in latest version). I've never seen it as an option in Sprint Navigation, although I only first used Sprint Navigation when I got my TP2 back in Nov 2009. To me, this is a very useful feature that it seems they would really like to keep, and I never noticed it being buggy in either GMaps or Bing.

Just curious if anyone is aware of some technical issue or other logical reason that this feature would be pulled from an app.