Amazon removed it also buyer profile . used to use that to see if the buyer was a seller trying to scam you out of your items. amazon is making the site one sided for (buyer).
most likely to hide secret buyers so you can't check their inventory.
It's meaningless because unlike eBay, you have no idea who the buyer is, until they place an order. You can't block any buyers, regardless of previous interactions with them. So leaving feedback is a futile gesture on Amazon.