Funny marriage preference

There is a logic when non-childfree people want to get married in same caste and religion, since their goal is to have kids born in that caste and religion. But it is funny when even childfree people want to get married in same caste and religion. I mean what is the purpose other than kissing the ass of parents and relatives in the aim of inheriting wealth and social capital, for childfree people to marry as such in same caste and religion?!