Could somebody be as kind as to clarify what the word 'comfort' means in the following question and answer?

I think I've got a Principal Contractors' health and safety officer that is getting his facepiece fit testing mixed up with his pre use fit tests.

Do I need to fit test disposable facepieces that are worn for ‘comfort’ purposes?
38 No. If the employer’s risk assessment clearly demonstrates that the respirator is being used for ‘comfort’ rather than as a control measure, then fit testing is not required.