You read these codes on every outdoor and industrial AP, antenna, PoE injector, and enclosure spec sheet. The injector zip-tied under an eave is the classic weak install. Spec the enclosure to the actual hazard, and translate NEMA to IP so you can compare US and international gear on the same terms.
A rating describes a lab test, not a guarantee. Verify the manufacturer's stated rating on the real spec sheet (for IP68, the stated depth and time), and match it to the real hazard at the mount point.
Have you ever needed to explain these IP ratings to your customers? Any tips or analogies that have worked for you?