Good questions.
The loaner wasn't specifically bought for that purpose. It was my former EDC before acquiring the 3" M16. It's still a solid knife, so I chose not to totally retire it just yet. It also comes in handy for the occasional prying task, so if I totally ruin it, I won't be much concerned. "Oops."
(I hate it when a knife falls, though. You see it falling toward the floor and you just think, NOT THE TIP!)
It works fairly well as a loaner, because the handle fits well in the hand, and is a decent size and weight (probably 5 oz., give or take). Thus, the handler, especially inexperienced ones, are quite aware of the knife in their hand and won't fall out. My EDC, on the other hand, is just under 2 oz. and they'd hardly feel it in their hand.
The only problem with loaners is the release method of the locking mechanism, as most people have to be taught how to close the knife. I've seen it plenty of times with liner-locks, and I think it's because they just don't see it.
If I were to choose a knife specifically for loaning usage, my first choice (off the top of my head, mind you) would be a BM 921 Switchback. It's pretty, styled to look like a butterfly's wing. It has the small blade that some folks would be more comfortable with. Last but not least, the AXIS lock is fairly visible and easy to explain. "Pull that back with your thumb. Push the blade forward with your finger."
Edit: On the other hand, I'd completely forgotten about the Benchmite.