Noticed that the price fall from $31 (Jan 2018) to $8 (Mar2018). How can investor make profit from this kind of coin?
It depends which period are you looking. Oct 2017 1DMD worth $6.5
DMD masternode create 214.419 DMD monthly income, now that the price is almost at a minimum, investors can earn $1,702 monthly. (this is info from masternode.omline)
So, you as a potential investor will get your monthly earnings, but still, you have an initial investment of (in this case) 10000 DMD.
You can say, there is a big risk. But this is cryptocurrency world, everything is a risk. Just think, guys who buy BTC when they touched $20k, where is his profit today from BTC?