A capacitor does nothing against a static discharge.
[/quote]So long as the layout is not horrible, a capacitance at the input means the input sees a much lower peak voltage than it would otherwise do. Consider conservation of charge. If you start with a standard human-body model 150pF capacitor charged to say 4kV, and you connect it to a (currently discharged) 100nF input capacitor via a resistance (value doesn't matter) then the end result is that the charge that was previously stored on the small capacitor ends up redistributed between the two, and the resulting voltage is (4kV*150pF/(150pF+100nF) or about 6V.
I will agree with you that a TVS or similar device is a better choice, but it's not true that a capacitor does nothing. The OP was asking if there was any reason not to remove a capacitor from an existing design. If there is no other ESD protection in place and the capacitor is all he has, then this may be such a reason.
