Comment by saltedmd5

This is why vertically-sliced product teams work - they minimise the communication and coordination overhead associated with Doing a Thing(TM), while layered or function-specific teams make everything take so much longer - particularly as the formal documentation and communication overhead grows enormously when different teams are accountable for different aspects of the same system. When a small team owns an independent(-as-possible) vertical slice, accountability is shared and the need for well-documented communication is largely mitigated.