Who's that kid with you? That looks like me.
As Paul mentioned, high spots on a strike can rub up against the plastic cases and wear the strike. This is almost always what happens with the dome on the Aladdin Taj Mahal strikes, because the dome is higher than the rim (and because it is gold plated). If you look at a worn capsule, it usually has a ring where the high outer part of the rim has rubbed, which tends to protect the design. But, when a portion of the design is higher than the rim, you will see a small circular wear mark near the center of the capsule. We hardly ever notice wear on the rims, but it's more obvious when it's on the design.