How does that provide an advantage over having the same data-center on the ground? The starlink satellite still needs to communicate with both downstream client

How does that provide an advantage over having the same data-center on the ground? The starlink satellite still needs to communicate with both downstream clients and some kind of upstream link (whether that link is geographically above or below it doesn't seem to provide any obvious advantages for the starlink satellite itself, and the advantages to having the datacenter on the ground are numerous).