A listing is patient. It sits there for as long as you need, and because it will still be there tomorrow, tomorrow is usually when you look at it again.
A show ends. Somebody is in front of a camera with a table of work, and when they are finished they switch the camera off. You either saw it or you did not.
This is not a trick to rush you
It would be easy to read a countdown as pressure, and plenty of shopping is built that way — a fake clock on a page that resets when you reload it. That is not what this is.
The ending is real because the person is real. A potter with forty pieces and an afternoon cannot photograph, list, describe, price and ship all of it and still make anything. What they can do is put it on a table, pick each piece up, say what it is, and let people bid. The ending is just the moment they put the last one down.
What it changes
Three things, and they are all about attention.
The seller gets to explain. Not a caption — an actual answer to an actual question, out loud, while holding the thing. Somebody types "is the handle comfortable for a left hand" and they turn it round and show you.
The buyer gets to compare, against other people rather than against an algorithm. A price nobody will pay is visible immediately, and so is a price everybody will.
And both of them get to finish. The item is sold, the money is held, the thing gets packed. Nobody is waiting for a listing that may never move.
Winning, and the clock after it
When you win something in front of the screen you have thirty minutes to pay. That is short on purpose: you are there, you meant to buy it, and the seller is still packing the last one.
If it ended while you were away — a timed auction you set and forgot — you get twelve hours from the first time you open it, because you were not there to be asked.
And if a winner does not pay, the item is not simply relisted into nothing. The next bidder is offered it at their own bid. They did not expect the message, so they get twelve hours too.
None of that is about punishing anybody. It is about the piece ending up with somebody who wants it, while the seller is still at the table.
See what is on right now, or read how a show works before you join one.