Actually it is quite new, they didn't just trap antimatter they trapped a whole anti-hydrogen atom, the reason this is significant is hydrogen atom don't have a charge and slip through conventional magnetic fields so can;ts be held in the same way as anti protons or anti electrons.
Antimatter bombs? really? Unless some major advances in antimatter production and storage happen this is not a worry. At current levels it would take several thousand years to accumulate the material needed to create even something close to a small nuclear bomb. Not saying this could ever happen but even if it did what would be the point? we could end humans with nukes a helluva lot quicker.