In the case of 23andMe users do own their data. And if they download their data and then request data be deleted then they are the sole owner. But if interested in genealogy, kinship, and some of the more actionable SNPs (e.g. those in drug ADME) then the 23andMe interfaces is informative and even useful medically. I have uncovered two medically useful variants. And some fun ones too: the speed with which I metabolize caffeine.

Their interface is also better than AllofUs.