[sailfrog]

Let's imagine you head over to the DMV over lunch to get your license renewed. Rather than have a line of people being served via FIFO they randomly pick who gets serviced next. Your lunch hour expires before you get your license renewed, meanwhile other customers barely have to wait thanks to the random selection. Rushing back to work you get pulled over ...

Silly example I know but FIFO matching is consistent with this idea of fairness. Without it it's possible that market participants could keep getting jumped by the random selection such that they never get an order execution.