Also a less Redstone and concrete limits so you don't need to worry about those when building a tram. Like 2-3 Redstone blocks or so

Lower the fuel usage?

Would these need tracks? If not, how would they differ from trucks?

its basically a truck with more decorations and less flyblock requirements

It would seem more reasonable for the trams to have tracks like they do irl

Yea maybe either rails on ground or overhead power (basically must touch a rail block like iron bars/grindstone)

Overhead power using grindstone/iron bars would greatly limit what a builder could do. I would just keep the same system trains use

https://i.imgur.com/bEpm7sV.jpg Like this

Chains or grindstone could work as a way for them to move