Primary lighting is dumb and controlled by switches.
Secondary lighting/mood lighting is smart and has the ability to be color changed and timing controlled.
That said, 'smart' systems love to lose connection or their settings and do the wrong thing too frequently.
There was one time where it went on the fritz and ultimately fixed itself when I restarted my phone (wish there was more troubleshooting or audit logging, but that’s endemic to all Apple products not just HomeKit)