Don’t panic, Ferrari should have a bit more experience and knowledge in building engines than you and me. A thing which you don’t understand or don’t see the advantage in does not have to be a bad thing.
Also, what would you expect a split turbo to bring Ferrari in comparison to Mercedes and Honda? Why do you think that this is the only way to go? Especially considering that both other manufacturers have developed the split turbo design for many years now and have tons of more experience?