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 

#2 Cash-in on Seth Rollins - A failed cash-in will establish Seth Rollins as the face of the company

Rollins retained his Universal Championship at Money in the Bank

By cashing in the Money In The Bank contract on RAW, I do not mean that Lesnar is winning the Universal Championship. Lesnar can even fail in his cash-in match just to elevate Rollins as the face of the WWE. We all know Vince McMahon had Lesnar eat the pin at WrestleMania 35 just for the sake of establishing Seth as their top guy, but somehow the Architect has not gotten over completely.

He still needs some push and thus, Vince McMahon could have called back his heat magnet, Brock Lesnar on TV. I mean even if Baron Corbin steps up against Brock Lesnar, the crowd will cheer for the Lone Wolf.

Brock Lesnar failing to defeat Seth Rollins in his cash-in match will surely help the reigning Universal Champion's status as the company's biggest face. This failed cash-in can most likely occur at WWE Super ShowDown.