If you're from an undersampled population (e.g. Africans), having more public data is useful for improving large scale genetic research. That's how we find thin

If you're from an undersampled population (e.g. Africans), having more public data is useful for improving large scale genetic research. That's how we find things like ghost lineages. Most people's genetic data is significantly less valuable for research without other info (e.g. medical history) though, so I certainly wouldn't consider that universal advice considering the obvious privacy implications for you and your extended family.