I agree 23 and me database is valuable but more for the second reason
I think the 23 and me data is not sequencing data but genotype data. So it only looks at a certain type of mutation in a limited set of ~500k known mutations. I may be wrong so please correct me if so. So you won't find as many rare mutations in this data, or non-SNP mutations. Also I don't think they have robust clinical data for all subjects, it's just self reported. Again I may be wrong, I haven't done a 23 and me
This is a big deal for drug development. Each drug basically targets one protein. So you need a genetic marker that has a large effect size and is well correlated with a clinical phenotype. Not having clinical data is a big issue here. Also, 23 and mes database is not designed to find large effect size mutations -- their advantage is scale, and I think they only measure known mutations, so they are good at picking up common mutations with small effect sizes in common disease. The depression study they did is a good example of this application
But that type of study is low value for drug dev. You want large effect sizes. So if you have a big dataset, you want to find rare mutations with large effect sizes that are linked to extreme phenotypes, not common mutations with low effect size linked to common phenotypes. Basically finding more PCSK9 type mutations. Having only genotype data rather than sequencing data really hurts here
That's why I much prefer something like the Regeneron Genetic Center to 23 and me. They get robust clinical data, do while exome sequencing, and collect data from targeted populations where signalnis easier to discover.
In fact GSK was part of the RGC consortium but dropped out, dunno why. This may be their "rebound" from that
Again my assumptions about 23andme may be off bc I haven't used their product