My D has had no trouble with the on-campus wi-fi. As momlax says, there are some random spots where it’s patchy, but they are limited and pretty well known. Unless your D/S has a room in one of those rare spots they really won’t need the ethernet cable- and as momlax found, the students view them sort of like pocket protectors in my parents generation: you can explain the practicality, but all they get are the optics! But- they sell them in the campus bookstore if D/S gets there & decide they want it. If you are packing for first year, don’t worry about it!