if you have free power then you should mine but my advice dont mine bitcoin. try other mineable coins. they are easy to mine and very much profitable than mining bitcoin.
You are correct , mining Bitcoin is pretty much useless on a PC , you need ASIC for that.
https://whattomine.com is the best place to check based on GPU, CPU, ASIC
You can also check
https://electroneum.com, which tries to bring mining to smartphones
Thanks! I'm really thinking about investing in a middle of the line rig with a pair of 1060s in it just to see where it takes me. I could simply place both of the Nvidia in one pc then purchase new cards and put them in one of the pcs I have now.