Let's be totally honest here, security nuts alone just don't cut it... with a cheap set of pliers you can spin them off easier than the stock nylock nuts if they are left exposed.

Right now your expensive tent could be haphazardly attached to your rig with 8 cheap no-grade 13mm nuts and a small strap of who knows what grade stainless flat bar. Your stock mount is easily cut or bent and the junky overseas Nylock nuts come loose with vibration (like off-road driving).

Anyone can quickly unbolt or quietly cut just 4 bolts, throw it in their truck, and drive off with it if they are prepared... these mounts let you leave your tent on your rig without worrying about leaving it unattended.