Erg gets a bit of a bad rap from coaches, IMO. The stimulus is slightly different, but there are times where there’s benefit from zoning out and putting down power. I mix my workouts now, whereas years past with TR I’ve done them all in erg. Recovery/easy rides I’ll do in erg. Sometimes on the days where I’m pushing limits of time in zone, I’ll start the workout in standard/resistance, then switch to erg for the last portion to reduce the mental burden and just focus on turning the legs over. I do all my testing in standard mode now.