Since this has been asked as sincere question, I'll try to provide an elaborate explanation. The question is what's the utility of the caste today. Before answering it, why shouldn't we think about caste still existing in Indian society despite all the attempts to reform it? https://twitter.com/Ankur72313142/status/1362311687932674049

The reason lies in the unique conception of caste. Caste is not just another social category otherwise it would have vanished under the impact of all the rapid socioeconomic changes which modernity has unleashed. But caste has shown remarkable tenacity.

The answer is: Caste is a kinship based social category. It's very similar to how extended family still exists despite all the constraints. Since many castes have their numbers running in millions, we forget this kinship aspect. But we just need to look around.

As a member of society, unless you're living in urban metropolis as a migrant, what connects you with other members of the society? In a village, you've your extended family having common ancestors who belong to the same caste. If you expand your horizon, again the same.

Events like birth of a child, wedding, death of your family members etc., it's your own members of the caste who connect with you primarily. It doesn't mean you don't have friends from other castes but you've a given group of kins who will stand with you.

When the search of bride or groom happens, caste helps in restricting the search group size while other members of the caste provide valuable information. Again, a new bond of kinship is formed with the help of members of the same caste. It lowers the cost of information.

In rural areas, when caste serves such vital functions, why won't people stick with their own caste? Humans prefer their own group over any other group and no intellectual labour can change this very human nature. Caste plays a vital functional role in their life.

Ultimately, contrary to what liberals believe, society is not constructed rationally. They evolve based on the selections which knowingly or u knowingly made and were later codified to sustain it. As long as bond of kinship exists, caste will exist in varying forms.