Two main reasons: 1) BT does not work quickly or reliably for ad-hoc connections. Have you tried using GameKit? It takes >45 seconds to ad-hoc pair (if BT is co

Two main reasons: 1) BT does not work quickly or reliably for ad-hoc connections. Have you tried using GameKit? It takes >45 seconds to ad-hoc pair (if BT is cold) and does not always work and 2) BT is very unreliable across platforms. But requires an internet connection but is fast and reliable compared to the alternative. Time will tell if that is a more compelling compromise. A lot of the applications using the Bump API are built on the cloud, so they would be useless without internet anyways.