For rail networks that travel outdoors, it always seemed just a tiny bit weird to me to be able to have a seat and a control system in your minecarts, but no cabin to keep passengers out of the elements. The full-cart tank produces a similar appearance, but it's not compatible with the seat module. The enclosed cabin wouldn't actually need to do anything gameplay-wise, although it could perhaps reduce damage from attacks made against players in the cart.
For rail networks that travel outdoors, it always seemed just a tiny bit weird to me to be able to have a seat and a control system in your minecarts, but no cabin to keep passengers out of the elements. The full-cart tank produces a similar appearance, but it's not compatible with the seat module. The enclosed cabin wouldn't actually need to do anything gameplay-wise, although it could perhaps reduce damage from attacks made against players in the cart.