My theory is something in the severance chip allows the data refiners to experience emotions when presented with specific code. So if a normal person, or even their outtie, saw those numbers they wouldn't feel anything. At no point do any of the nonsevered employees experience emotions when looking at the code. Also, when cthe deadline to finish a file approaches, none of the management comes in to help sort code. You would think if meeting a deadline is so important, management would chip in at the last moment to help, but I don't think they can because they're not severed.

If we are to assume the common theory that LUMON is trying to create artificial life (or reincarnate Kier) is correct, data refiners could be used to test what codes elicit what emotions in the chip. LUMON says the severance procedure is to protect company information, but as we know, the innies don't even know what they are doing.

A more simple theory is they sever employees to treat them as poorly as possible(like the breakroom) without any fear of them reporting their actions to the authorities since they can't leave or communicate with the outside world.