In addition to what the others said regarding disassembly, it's a lot easier to distribute (and train remote technicians to use/maintain) a test cartridge to se

In addition to what the others said regarding disassembly, it's a lot easier to distribute (and train remote technicians to use/maintain) a test cartridge to service centers around the world than to set up the $xx,000+ bespoke bed of nails test fixtures that you would use on the production line.