I can only pay for 12 hours electricity per day so I will be mining Ethereum through 12hrs only, as a rig owner do you think it's worth holding on to my mining rig or I should sell the rig and bit coins instead.
Depends… if you are making money from mining then keep mining. Do you have cheap electricity? What’s your hashrate? What’s your rig’s ROI?
I personally don’t like to waste time with mining. Holding the coin brings less headaches. Your mining devices will need maintenance and they’ll get broken sometimes. You don’t need to deal with this shit when you are a holder.