eBay disappearing/scam buyer. What’s the angle?

[Bilkob]

I’m a reasonably experienced ebayer, mainly selling, lots of pushbike stuff, I buy a few bits and pieces too
Recently ‘sold’ some nice wheels (£680) that were ‘bought’ by a 1 feedback bidder, based in China with a silly letters and digits username.
I didn’t have time as the auction ended to cancel their bid, and predictably they’ve disappeared, no contact, no payment, etc……
Interestingly, when I tried to make contact through the eBay app, it stopped working, and I couldn’t send a message
My question is more out of curiosity than frustration, I accept that every now and then, on a Worldwide platform things will occasionally go wrong.
So, as per title, what actually is the angle here? Is it to scam me? How? Just a bot ? Why?
As I said, just curious rather than upset or worried……
and if anyone wants a nice pair of Chris King/Enve disc gravel wheels , well, I’ve still got ‘em 🤣