The warning light might matter for squawk reporting (pilot to maintenance bug report, if you will). But even if the pilot notices the warning, if they don't kn

The warning light might matter for squawk reporting (pilot to maintenance bug report, if you will). But even if the pilot notices the warning, if they don't know about MCAS, then they don't know about "MCAS upset" which can result when MCAS acts on bogus AoA information. And this particular variety of "MCAS upset" quickly induces a mistrim, and high airspeed. So I'm unconvinced the indicator is a "safety" feature in-flight that will result in any different behavior on the part of pilots in an "MCAS upset" situation. It is a mistake to think that trim is only about attitude (nose up or down relative to the horizon), it also implies an airspeed. Nose down trim effectively translates into a higher airspeed, all other things being equal. If you reduce power, the plane will nose down (this is a function of positive static stability, a FAR 25 certification requirement for transport category airplanes), and the plane will stabilize to maintain the airspeed implied by that trim. Add power and it will climb, to maintain the airspeed implied by the trim. The central problem is still that the pilots weren't trained about MCAS in either it's intended working condition, or "MCAS upset", or how the airplane behaves with autotrim disabled and therefore without the benefit of MCAS. The pilot not being aware of these three of these behaviors is just flat out wrong. It's bad enough they weren't also required to demonstrate competency (knowledge and practical test) for all three.