Operator configuration best practice

Config
1

I am confused with the configuration of istio operator. For example:
Tracing sample can be set in meshConfig:

  meshConfig:
    enableTracing: true
    defaultConfig:
      tracing:
        sampling: 100

and also can be set in values.pilot:

  values:
    pilot:      
      traceSampling: 1.0

I want to know the priority or scenario to set the config via meshConfig, values or components ?