Until I saw these posted in an earlier thread, I was unaware of their existence. If I understood the ebay description, they're metal buckles set against patent leather. If the shoes aren't of the same material, the patent may stand out, possibly in a garish way.

For formal footwear, I use white bronze buckles mounted on 18th century reproduction shoes - saw something very similar on a gentleman in Scotland.

These shoes are far more preferable to me than Mary Jane's and much better in appearance than ghillie brogues with formal wear.

Slainte yall,
steve