At the end of the film we learn that Luke
wasn’t actually on Crait and had projected himself along with Han’s metal dice-on-a-chain.
After the game is up and he stops
projecting himself, the dice stick around for a while longer.
Why did he do that? It seems that was the only thing he continued to
project. If his intent was to buy time, why continue to exert the effort needed for the dice
after he accomplished that purpose?