You mean use HDD to mine Proof-of-Capacity such as burst coin? If so, then the answer is no. Mining calculator such as
https://blocks.fastpool.info/calculator &
http://burstcoincalculator.com/ show that you only get about $1-$2/month, without calculating electricity cost.
I don't know much about decentralized cloud storage, but
https://storj.io/ homepage mention you will get $0.015/GB/month which mean you could earn up to $120/month.
storj.io requires bandwidth with proof of capacity doesn't.
Ideally, someone would create a public "proof-of-retrieval" system rather than just simply proof-of-capacity.
If someone were able to build proof-of-retrieval, ideally with proof-of-compute (assuming you had a fancy enigma of sorts), you could do distributed applications effectively.
Electricity costs are hdds are tiny. An hdd running takes around 5 watts of energy. That totals up to 3600 watt-hour per month. My rate is $0.10 per kilowatt-hour, so $0.36 in electricity cost per month off $1-2 profit still.