well, high energy stuff is a WMD but also a nice fuel. i'm not against the idea of using AM as a weapon. it would be fun to sneak it on-world and then just kind of erase 30% of the planet's mass in a giant superexplosion.
another thought: how many tons of AM is 1000 "units"? is every planetary settlement essentially a huge planetkiller that could go off at any time?
no wonder people join spaceships where they are de-facto slaves with a 10 minute life expectancy!
From the looks of the icon, it has the rough shape of an oxygen tank used for diving. Makes sense - easily man-portable at an individual level yet easy to move in bulk on pallets (during WWII pretty much every army moved their fuel around using 5-gallon "Jerry" cans and nearly nothing else, not even dedicated tanker trucks). However, I suspect that the antimatter foam (or is it antimatter pellets as described in Sindria's planet description? Which would kind of make the fullerene shells described in Fuel's description feel a bit off as they're pellets and not a gas, liquid, or foam, suggesting that a shell would be unnecessary, not like Fluorine anyhow) is pumped out of these tanks and move into the ship's dedicated fuel tank (or in the case of tankers, giant fuel cells). David would have to clarify that as loremaster.
As to every planet being a giant bomb - well, both Sindria's planet description and the Fuel item description describe AM fuel as, and I quote, "relatively stable fuel pellets" and "Fairly safe". So I think it's a bit like C4 explosive, where it's difficult to set off unless a specific set of circumstances are met; in the case of C4, it can only be set off by the shock wave from another explosion (like det cord), and shooting it with fire arms won't even set it off. Not sure how you might weaponize this relatively stable composition, it's not exactly your everyday explosive.