The advantage of family burial plots is for the convenience of those who visit the graves.
We have a family cemetery in Queens for my Paternal mother’s line. When I go to visit, I can visit the graves of Parents, grandparents, great grand parents, aunts, uncles, great and great great aunts and uncles and assorted cousins.
We pay much less to have the entire section taken care of by a landscaper each growing season that the cemetery would charge on a per grave basis.
We were able to erect a massive family name headstone to which married last names are added, but all that is required for a new internment is a small footstone. This costs 1/4 of an upright stone per person.
My maternal line is in 5 different cemeteries in the greater NY area. It takes two Sundays in Late August to make the ore RH visits. The deceased appear lonely, just one or two familiar names in huge cemeteries.
I much prefer families to remain together.
It also makes genealogical research easier.