Even so, external tanks are more exposed to damage. Personally I’m not so concerned about explosions but leaks. It’s a whole of fuel to lose at once… The large capacity might actually be a downside. It’s the “all eggs in one basket” effect. But it is possible to build around an external tank and give it more protection that way. Location, location, location… is the key, I guess.
But also, if you install a normal fuel/water tank, you can’t install a storage battery in that same tile. Truck and car batteries are OK though. In that sense, an external tank might open up a bunch more slots for storage batteries if one needs them. But then again, even 1-3 storage batteries is super plenty, right? I mean, 64kb oughta be enough for anyone, haw.
I’d assume an external tank is super useful for one-time low-risk transport operations. Install tank, haul liquid, uninstall tank.
When can we transport whiskey in vehicle tanks?