The main downside to metal clips or rings are that they scratch the camera around the connection point. This used to be no big deal for most folks. For those that it was, there were little leather pads attached to the ends of some straps to protect the camera from the metal hardware.

Some such straps came with metal clips rather than 3/8" loop ends.

In the present era, it seems that everyone is obsessed with their electronic devices being cosmetically flawless. Most people put protective covers on our phone screens, camera screens, phone backs and sides, etc. So metal hardware at the end of straps that would come into contact with the camera have fallen out of vogue.

But there are still more than a few "boutique" strap makers that offer such straps. Just do a google search for "vintage camera strap" (also select "Images" to easier see what the different results look like) and many of them will have metal clip ends on them.

Then there is Op/Tech, who has a near endless number of connector styles that are modular so they work with all of their strap, sling, and harness styles. The ends tend to be very affordable as well, usually around $8/set for most types. So you can buy the strap you want, then mix/match various ends until you find what works for you without breaking the bank.