For hiking, I switched from steel adjustable slides to plastic hardware in the early 1980's. I use Marmot and Osprey packs with plastic hardware over 20 years for extended treks in the Sierras, Denali, etc. with no problems.
Plastic quick release failure? Preventive maintenance - check all gear that it is in working order; clean sand, dirt, or debris from mechanism; and replace any worn parts.
What would I do if I had a failure on my TransPac or TransPlate quick release and could not fix it right away? I would just loop the adjustment strap though the D-ring and dive.
Can I still exit the water with moderate surf over the rocks and boulders then hike back-up the steep cliff trail back to my truck? Yes, I can.
Can I loop and tie the adjustment strap at depth or while bobbing on the surface of the water? Yes, I can.
Do I think there is some risk of failure? Kind of remote. Most likely a rough exit slammed into the cliff or rocks by a wave or falling down while hiking against a rock. The old tank hit it scenario does not apply to my quick releases.
To each his own. I am into quality, comfort, performance, and reliability.
Dive Rite fits my needs.