Fluffy Bunny Feet
Banded Mongoose
That is one reason I don't like them. IRL I've seen that fail. A tanker (product tested by our lab) delivered a load to a employer of mine unloaded a small amount due to protocol and tested from the storage tank (last thing in was the same product) it was contaminated. Cost a small fortune to the tanker company to clean it and the load had to be returned and replaced as they hadn't cleaned the pump used adequately.Simple Mechanics task if that. No more than d6 man-hours for the whole compartment, and that is erring on the side of being overly labor intensive.
I see them as dangerously impractical when it could result in the loss of the ship and crew if the area was not properly decontaminated before refueling.
Also it restricts you to the two functions. A modular fuel tank could be replaced with a cargo module, passenger module, science module or luxury module. Core to the idea is using modules to repurpose a volume of fuel storage if the ship needs to perform a different function with lesser (or no) jump.