The transport mode doesn't replace being able to use the shift button to get a transport bar.
Regardless, putting the Minilab 3 in transport mode in a user preset does not work in Ableton Live. The controls do not function properly, unlike when in DAW or Arturia modes. The transport mode control "STOP" toggles playback and "PLAY" does nothing.
This controller is so close to being decent, but misses the mark (again). I've got a boxed up Keylab mkII that didn't make the cut either. Arturia seems to develop half-baked controller solutions and then let them rot. I wish the division managing their controllers was as on top of things as their plugin and hardware teams.