If hoping for assignment: Strategy is that it will be assigned and the price is expected to increase over the weekend so that you can sell for a profit. If hoping to not be assigned: Avoid paying commissions to close out.
There is some risk involved: once the market closes you can't do anything with your positions. So say the market closes on the last day of trading for an iron condor and the underlying is just above the lower short. You're safe right? Not really. Say a major earthquake strikes or a war breaks out? The options generally don't settle until the next day. It's worth a few bucks to give the market maker his $0.05 plus commissions and at least close the short.
Risk of an option being exercised after the market closes extends until approximately 5:30 PM New York time the same day. The strategy I like to use when Vols are high is to own the product and sell the at the money straddle and hold it through expiration. Upon expiry, The Stock gets called away and you keep all the short premium for a nice profit Or an equal amount of product is deposited in your account and you have scaled in or have a lower cost basis. Then I sell another at the money straddle and do it again. The strategy avoids going back to the option market to unwind your position. Those market makers only see you once.