Hashprice rolls four variables into one: bitcoin's price, network difficulty, the block subsidy, and transaction fees. When price rises or difficulty falls, hashprice climbs and marginal machines become profitable; when the reverse happens, the oldest rigs go dark first. It moves daily and every mining desk watches it the way traders watch the spot price.
The unit matters. A hashprice of $35/PH/s/day means a machine producing 0.2 PH/s (200 TH/s) earns about $7 of revenue a day — before electricity. Whether that's a business or a space heater depends entirely on the operator's power cost.