"And let's not forget that the value of these coins I am holding is increasing at the same time."
But so is the mining difficulty but your hash rate is not (unless you pay for more).
I think it's probably a better investment to simply buy Bitcoin and other cryptocurrencies, personally.
If you can benefit greatly from referrals, well that's probably your biggest source of income then on these mining platforms.
I do agree with you 100%. However, I am a trader addict so to speak. Well, to be fair I am an everything addict!
So what mining does for me is prevents me from playing with these coins in the markets.
It locks me in to two year contracts where all I can do is watch. From my perspective, this is a very good thing :)