I can't really wrap my head around this but I know a thread was created to address this and possibly stop it but the $10 bids are still pumping up all over the place over at Godaddy auctions.
What they did was stop backorders from sniping domains pre-closeouts. You could previously place a backorder when there was just a few seconds left or so in the auction. Too late for the auction to register the bid, but your backorder would then preempt the domain from going to closeouts, and you would win it outright rather than it going to closeouts.
Somebody automated and started doing this on a large scale (thousands of domains a day). GoDaddy eventually put an end to backorder sniping, and it's no longer possible. Once a domain auction ends with no bids, it goes to closeouts with a $11 BIN, regardless of whether or not someone places a backorder before that. The only backorder bids that count are those that go "live" as auction bids.
Anyone can still buy and place backorders, but in effect they're no different than placing a regular $12 bid. When you place a backorder it shows as a $10 bid. If you buy a large quantity of backorders (100+), you get a discount so that it becomes a bit cheaper than placing a $12 bid and winning. I suppose that's why someone is doing it. However, I also see many domains have 1-3 seconds left, and then get a $10 backorder bid. In those cases, I guess whoever is doing it is trying to snipe the domain with a backorder. They probably don't know that GoDaddy closed the backorder sniping loophole.
A $10 bid is just as prone to automated bots bidding against you, so I assume that most backorders these days "fail" to grab the domains being backordered for the base backorder credit price. Few domains at GoDaddy these days end with just 1 bid, be it a $10 or $12 opening bid. Once a bid is placed, there is a high probability that bots will bid on it
because you bid on it.