Mobile weapon platform

What’s the purpose of adding these mobile weapons platforms?
What are the benefits compared to sentries?

They are like sentries, but:

  • they are bigger (occupying cargo space not being drones)
  • they are easier to kill (being bigger)
  • they can be probed
  • they cannot be used in PvP
  • cost (a lot?) more,
  • need ammo
  • need modules

I cannot find a single reason to not use sentries instead of your MWP