Long story short, a MKR CDP is called a collateralised debt position; you are using our ETH as collateral for DAI debt. You can get DAI from your CDP and then do whatever with it. You get the ETH back when you repay the DAI (which is pegged to 1USD via the market and smart contract). Be mindful that if you don't leave enough margin your position can get liquidated.
MKR is the fuel of the system.. 2.5% fee is paid in MKR, and that MKR is burned. Which means total supply is set to decrease every day, and thus price to increase.
+ stable coin managed by smart contract; used already, use will grow + you can create collateralized LEVERAGED positions + MKR is probably a very good buy + new thing, people still don't understand it
- oasisdex is shit - bit complicated to understand - 2.5% fee - 150% (at least) of collateral needed to open CDPs - people get burned with low collaterals these days