USL plays a 28 game schedule (14 home games) and has averaged 3,217 folks a game this season – so not an insignificant number of eyeballs over the course of a season. The league is growing like crazy as it develops into more of an MLB style minor league with the big clubs owning and having full control over players for their affiliate. There are also independent clubs competing against the affiliated clubs.
A relationship with the Union could also mean other potential revenue generators like exhibition matches, summer camps, maybe even training camps for the Union themselves. The Union actually have a residence academy for high school aged players to focus on soccer while still doing (some) schoolwork, and the USL team is designed to be a bridge between those kids and MLS. The quality of play should be pretty strong, though no idea if the Lehigh Valley will support it.
Part of me thinks it’s possible that the announcement is at Goodman but that the team could play elsewhere on campus. Not sure 16k seats is necessary for USL, but maybe the Union think it makes sense when accounting for future growth.