There are two clear advantages: 1) Clear types and structs that are shared between client and server means that both can generate models based on a common set

There are two clear advantages: 1) Clear types and structs that are shared between client and server means that both can generate models based on a common set of data specs 2) Clients can have some autonomy in what data they choose to fetch. This is easier said than done but models may be set up to allow joins on datasets for custom model trees and reduced payload size by limiting the fields returned.