[jghn]

You can get valuable data from genotyping. SNPs contain the bulk of variation between you & me.

For your first question it depends on your definition of "companies like 23andMe". There are numerous companies that'll do a whole genome for you, but I don't know if any of them do the writeup about it that 23andMe provides. 23andMe did at one time offer an exome product, but stopped that a while back.

The largest hurdle is cost. Whole genomes, even exomes, are significantly more expensive than a SNP chip. As most would be users don't know enough to care it doesn't make much economic sense to offer those to the masses at the moment.

[astazangasta]

Actually about half of variation is private (not common) and commercial services will only look for common SNPs. So you will have some unique variants that would show up in a whole genome but not a SNP test.

[jghn]

True. I was trying to say that your average lay person is unlikely to know the difference enough to be a big deal