Without a resale path, your cloud mining return is capped at what the position pays out:
Return = mined BTC − costs
With one, the residual value of the capacity comes back in:
Total return = mined BTC + resale value − costs
A short example makes the gap concrete. Numbers are illustrative, not a forecast.
Say you put $10,000 into a hashrate position. Over the holding period it mines $6,000 of BTC, and costs (hosting, power, fees) run $2,000. That's $4,000 of value the position hands back over the term.
If you can't sell, that's the end of the story: $4,000 of net BTC against $10,000 deployed, and the capacity's residual value goes to whoever owns the hardware. Now suppose the same position can be resold for $8,500:
Total return = $6,000 + $8,500 − $2,000 = $12,500 → +25% on the $10,000 in.
Same mining output, same costs. The entire swing is that $8,500 of residual value: money you forfeit in a locked contract and capture in a liquid one. Resale isn't a line you can leave out of cloud mining ROI. Here it's the difference between a weak result and a positive one.