In recent years I have used mine lots. 5-6 times I have been hooked up in fishing line. A couple of times from dickheads fishing on the breakwater at the local kite beach. Most times from stray line drifting out in the sea. It's quite nice to whip out the knife, cut the line, keep on riding.
The line has cut a groove into a fin where it rubbed over the edge. There's no way I could break it. My greatest fear is that there might be a hook attached to the end.

Once I landed the kite on a deserted beach during a monster squall. I got the kite down ok but a loop of line hooked around my ankle. I grabbed the knife and cut the line. There was no way I was going to wait around and see what might happen next,
I used to be annoyed that the knife would sit in the ouch for years and get corroded. Rinsing in fresh water doesn't help. At $15 each I buy a couple at a time and just replace the corroded one. They still last a couple years ok.