I need to wear an insert inside my shoes, and found the lack of a strap across the instep in ballet flats made them unwearable.
Then I saw some RTW ones with an elastic strap across, and decided today to do something similar to mine to make them more wearable.
I may also dye some plain white cotton socks with Dylon's Pebble Beige to wear with them, as this works quite well as a 'close to nude' colour for me.
These look quite good with pants which come down over the foot which is how I plan to wear them.
The animal print ones in particularly look good with my tan wool pants, and since both of these have previously been hard to style this is great!