tl;dr:Technical leaders should be highly technical for 5 reasons: (1) Only way for CTOs / VPEs to be true judges of quality. (2) Allows them to make highly educated tradeoffs - quality, speed, launch dates, feature inclusion etc... (3) Enables them to command the respect of the entire team. (4) Highly technical people very often have a deep passion for technology. (5) Easier time attracting and recruiting other highly technical people.