Hi,
here are my two cents from medical device perspective.
A human being can lose just from his hands up to 1x10^3 cfu/cm^2. More in general, we are losing on average 10 g of skin per day.
From a medical device perspecive, this means that you might have a certain quantity of viable micro-organisms on your product, which could affect your initial bioburden.
From a regulatory perspective, depending on risk management and product intended use, you might want to reduce as far as possible the risk of infection.
Hope this helps