“Who are you interfacing with today?” Will it be in a dry climate, or on synthetic carpet, both of which promote ESD static zaps? Product designers rarely know. There’s no room for “But it fails 1 test in 100 and I don’t know why!” if you’re intending to make thousands of something, or if the consequences of failure are serious.  The difference between a prototype and a product is experience, planning, and worst-case engineering.  For a robust, reliable, and EMC-compliant product, interfaces like Ethernet, USB, RS485, etc must be well protected and filtered.