The idea of a wider planer is to take glue ups and clean them up. since
most hobbyist units are only 12-13 inches you work in groups of glue ups.

Well... you really shouldn't run a glue up through a planer. The glue will play hell with your blades. No glue, no poaint, just wood ro the blades die. Also, if you have any spring or cup in your glue up the planer might crack the glue joint.

Get a drum sander or wide belt sander if you want to flatten glue ups.