Equipment can be broadly split in sci-fi and fantasy. From the core manuals we have plenty of fantasy equipment, here we add sci-fi elements.

Balistic is a new kind of damage, it is a specific kind of Percing damage that comes from kinetic weapons (like real world guns); this means that resistance to Balistic damage will not protect against Percing damage in general, but resitance against Percing also protects against Balistic.

The other hand more Sci-Fi guns will inflict Radiant, Necrotic, or Force damage.

The design goal of the Sci-Fi armors is to make them better against Sci-Fi weapons, but still a decent choice against Fantasy.