Incorrect. A MKR CDP is called a collateralised debt position. It has nothing to do with betting on the price of ETH.
Youre merely using our ETH as collateral for DAI debt. You can draw DAI from your CDP and then do whatever Witt it and repay the DAI. Leave enough margin and youre fine.
Yes but you only get 2/3 of your ETH on DAI. Then you have to exchange the DAI to another currency, etc. Plus interest is 0.5%.
Also, here you can get a loan w/ ur account as collateral or any altcoin.