As the title says. We already have trains and bots etc. But we don't have something that helps with fluid and gas logistics. These little carts would be ideal to do that over short/medium distances.

Due to how fluids suck in Factorio... Barrels, stick to barrels...

Without deciding whether I like the idea yet -- I actually have no clue how to do this :-) Will check it out...

I've been using carts with barrels to move small volumes of Angel's less critical fluids/gases. Filtering half the trunk to full barrels and half to empty seems to work OK. Since the cart carries it's own empties to and fro barrels are not much bother imo.

Short distance I normally use pipes. But it quickly becomes spaghetti. Long distance nothing beats trains and fluid wagons. Barrels becomes a hassle when it is medium distance, where pipes are not viable anymore, when you don't have space for added complexity of barrel logistics, and when you can't fit anymore train tracks and stations. This is where a tanker cart can work well. I think there is scope and need for 'mini-trains', where the carts could fit the spot.