2 reasons Brock Lesnar should cash-in his Money in the Bank contract on Seth Rollins and 2 he should cash-in on Kofi Kingston 

#1 Cash-in on Kofi Kingston - SummerSlam Showdown between Reigns and Lesnar

This will happen soon. Believe That!

It is no secret that Vince McMahon wants Roman Reigns to become the face of SmackDown Live hence, he moved him over to the blue brand in the Superstar Shakeup. Now, the problem in pushing Reigns straight into the title picture is that the current champion is more popular amongst the WWE Universe. Hence, the fans would once again turn their back on Reigns.

WWE wants Kofi to drop the title to a heel who can then lose it to Roman Reigns. The only heel who fits perfectly in this role is Brock Lesnar. I mean none of the SmackDown heels can put the Big Dog over. If WWE gives the title to someone like Kevin Owens or Andrade, the fans will cheer for the heels.

Thus, it makes sense to have Kofi lose his championship to Brock Lesnar before he can have a SummerSlam showdown with his old enemy, Roman Reigns. Reigns can win a multi-man bout at Extreme Rules to progress to SummerSlam where he can once again slay the Beast.