KU makes zero sense from a football perspective, the Big10 would get more viewers watching Bob Ross paint than KU football. It not like the KU v Nebraska rivalry was huge. It also further weakens the Big10 West. But maybe that changes soon anyway.
But if the Big10's goal is to get to 18-22 teams it makes a bunch of sense. KU is a top 5 basketball brand and playing 10-15 games on the Big10 Network might be tremendously valuable for a conference with a linear network. Also could mean a lot to FOX's basketball programming if they go all in on Big10 and replace ESPN's media rights.
If the Big10's first move is KU, that tells me they have at least a couple ACC or PAC12 big dogs from a football standpoint about ready to join also.