Damage. Pinhole is just as damaging to corporation that may result in leakage of password files, sales projections, customer records, confidential data, and mass encamping of external hackers infesting your company's entire networked infrastructure.
Slowing down everyone is also incredibly damaging to the corporation though. And as others have pointed out might even be counterproductive as workers look for workarounds to route around your restrictions which may come with bigger security issues than you started out with.
