Being around other kids helps kids learn social skills.
Most of us do that in school. Homeschooled kids can lack that depending on how the parent socializes their kids. Some homeschooling parents realize that they have to socialize their kids. Those parents put their kids in sports or scouts or other places where the kid can socialize. Other parents are oblivious that social skills are learned, then you can end up with some really awkward people out there.