Do Cab Signals really save lives?

I am curious if Cab Signals really do save lives? With automatic waysides being made from LED bulbs now, should the MAS for non-cab signaled routes be raised?

I don't think that "saving lives" was the main purpose, but it does help enhance safety (and allow for faster running).

No matter how bright the bulbs are, reliability of a wayside system still is subject to alertness of crew or vandalized signals or equiupment.
With Cab signals and ATC the speeds are enforced and any changes are sure to wake up the crew when alerter goes off or train is not brought in compliance with speeds.
Any failure of Cab signal apparatus outside or inside the train results in fail safe mode or restricted speed enforcement.