Antimatter is a terrible store of energy because it is "fail-dangerous". The failure mode is a catastrophic release of energy.
The closest comparison for endurance would be nuclear power. Its worst failure mode is meltdown, which while very bad is nothing like as destructive as an AM explosion.
And it gets worse! Suppose your AM containment fails in a carpark. The explosion will cause a chain reaction of car explosions.
Finally, there is the incredible inefficiency with which AM is manufactured. It takes gigawatts and many hours of accelerator time to create even minute quantities. Because the only way we know of to create AM is smashing things together in particle accelerators. There aren't many LHCs to go around.
In the far future, I could see technology advancing enough to where we could efficiently create/manufacture antimatter (e.g. from a star or something).
But the "fail-dangerous" issue is more of a user responsibility, and I don't see that being solved anytime before the above technology is discovered (if ever).
Peter F Hamilton surmised in his Night's Dawn trilogy that antimatter would be outlawed, but produced by large accelerators parked close to suns in unoccupied solar systems. It was still heinously inefficient, but the high price of black-market AM justified the cost.
Putting speculation aside, we know that AM is fail-dangerous. For all current purposes, we have better alternatives. For long-endurance power sources we have fission. For weapons we have fusion.
I cannot personally think of a common use where the statistical certainty of failure outweighs the risk.
A lot of the yield in H-bombs actually comes from the fission of the depleted uranium tamper - in the Ivy Mike test (the first real multi stage H-bomb) 77% of the yield was generated this way:
The Tsar Bomb test was restricted to 50Mt by missing out the 3rd stage - so it was primarily a fusion device. Had the depleted uranium tamper been in place it would have given the 100Mt the design was capable of - but with horrific fall-out.
My knowledge in this domain is quite limited, but maybe someday somebody will figure something out. Just the thought of antimatter existing is very cool.
The closest comparison for endurance would be nuclear power. Its worst failure mode is meltdown, which while very bad is nothing like as destructive as an AM explosion.
And it gets worse! Suppose your AM containment fails in a carpark. The explosion will cause a chain reaction of car explosions.
Finally, there is the incredible inefficiency with which AM is manufactured. It takes gigawatts and many hours of accelerator time to create even minute quantities. Because the only way we know of to create AM is smashing things together in particle accelerators. There aren't many LHCs to go around.