The advantage would be allowing you to reconfigure the array far more quickly, The drawback is that it would cost a huge amount without providing much benefit. As Strenoth mentioned, the precise placement is an issue: you would not do an observation while moving. They will have to be parked to the stability requirements.Cost: Those antennas weight about 100 tons each. Building 2 transporters for them was quite expensive. Building each antenna to drive around on its own would have cost a lot more. So the plan is to have a couple hundred antenna parking pads. Then you can move around a couple at a time, and have the rest observing.