Maybe for separation of concerns between data and UI?
The browser is not going to be the only client?
The vast majority of the time, the browswer is infact going to be the only client.
once you reach the point where its not, then build the api to suit the new client rather then trying to build one that does both.
But on the other hand, you can have a iOS or Android based app that depends on the same data. So the browser is not the only client in general, especially nowadays, I think?
Dramatically more important than any theoretical, abstract consideration in deciding whether this can work is what your teams look like. The client team should almost certainly own the BFF API, which has implications for skillsets and maturity.
If so, that doesn't handle the general case (native apps for instance)
In fact, you can see it as 2 decoupled kinds of database:
- the storage database
- the working in-memory UI database that holds the data represented (e.g. on your screen (GUI)).
The goal in general is to modify the data contained in this UI database and then to push the changes to storage.