Can I use the cabinet for CCTV, AV or other low-voltage equipment as well as networking?

Yes. There’s nothing inherently Ethernet-specific about the cabinet.

CCTV recorders, AV distribution equipment, fibre hardware, control equipment and other suitable low-voltage devices can all share the enclosure where their dimensions, weight, mounting method, ventilation and cabling requirements allow it.

A rack is really an organised mechanical framework. What you populate that framework with is considerably less doctrinaire than the word “network” on the product page might suggest.