If we were to have bigger maps and longer lasting battles, engineers could build structures that act as a resupply & free repair stations for tanks but tanks already come with a shit ton of ammo so there’s no use to that 
Good idea, and yes there is a use for it! I ran out of ammo! Invasion, Demolition, and assault maps have no tank resupply points. ONLY Conquest maps do!!! WHY?! That SUCKS! AGAIN maybe like WarThunder, and Battlefield V, tanks can resupply at a flag point/conquered base.
Also engineers should be able to build runways for planes, and planes can be rearmed, and repaired there, as well as be repaired by any friendly soldier with a tool kit!
YES THERE IS A USE!