Its mainly to get an approximate, I know its not accurate unless you have a power meter. I didnt know they posted power curves for turbos, I will see if mine has one. But room temp and tire pressures are generally constant.

Superdex - I normally do a 10min warm up, varing the intensity and cadence and I do get warmed up nicely but my heart always raises ALOT slower indoors on the turbo. Outdoors my heart will be in zone 3 within 5 min without a warmup, and me PE feels slow compared!!