> you win the ability to have multiple different frontends against the same backend, or run multiple backends against the same frontend. > you win the ability

> you win the ability to have multiple different frontends against the same backend, or run multiple backends against the same frontend. > you win the ability to upgrade/replace backend or frontend independently. > you win the ability to develop with multiple independent teams because the connection between frontend and backend is smaller and easier to define. > you win the ability to reuse generic backends over multiple projects... None of these are really specific to SPAs, they apply to any architecture with a separation of concerns.