On a stock or relatively close to stock engine, that seems like significant overkill. Truthfully, a single wideband monitor on a stock engine doesn't make much sense other than Wow Factor.

Widebands are extremely useful for tuning modified engines. Even the experts at Pierce Manifolds who have been installing fancy race quality carbs on a broad variety of engines use them. Lots of racers use them along with other gauges that most of us will never have need for. Cylinder head temp gauges and exhaust gas temp gauges, for example(s).

Wideband tuning versus seat of the pants and plug reading saves an enormous amount of time. Typically, this is done on a dyno, so the operator doesn't have to worry about reading the gauge(s) while also navigating the road or track.

Cameron
Portland