You want to launch a Rocket, but never launched any kind of Rocket before? Now you need "Rocketry" to build the Rocket-Silo.
You are affraid noone use barrels to transport any liquids? Now Fluidwagons are Endgame Items :D
What to do with empty Barrels if you get your Fluidwagon?
You need them to build your Fluidwagon!
Edit:
Mod renamed with same functions, but better explaning itself.