Francine Ruched Loafer

I ordered a pair of Reformation shoes in my usual size (US 9 / EU 40), but they ran significantly large. When I tried them on, there was a noticeable gap between my toe and the tip of the shoe, and they felt like they would slide off with wear. I didn’t want to deal with thick socks or worry about them slipping, so I went ahead and filed a return. Overall, the style was beautiful, but the sizing was unexpectedly big for me.

I tried them out on hardwood floors and with every step it felt like I was about to slip. Almost dangerously slippery. Are these only meant to be worn on carpets??