At Genesis-Mining - your contract buys a certain level of Hashpower on already set-up mining rigs. You are able to mine using different types of machines - for different types of Crypto-Currency (coins like Bitcoin, Dash, Ethereum, LiteCoin, and others) - all of these coins have different prices and values that are constantly changing.
Indeed, you will want to mine using the Sha256 contracts - if you want to mine Bitcoin in a lifetime contract - the other types of contracts for DASH and ETHEREUM are limited to a two year period of time. For all types of contracts they automatically take a service fee daily - you are paid daily on some contracts and on others you build up a small balance before transferring, which is done automatically for you.
Now, IF you signed up at Coinbase - you already have a Bitcoin, Litecoin, and Ethereum address and wallet for each coin. To mine DASH or any of another dozen or so coins that they offer mining contracts for - it's a bit harder to obtain a wallet - as Coinbase does not carry or support those coins yet. Having the wallet addresses from Coinbase for Ethereum, Bitcoin and LiteCoin will provide you a way to move your "mined" coins out of Genesis-Mining and into your own wallets at Coinbase.
Coins in your wallet at Coinbase always have an instant sell or buy price - yes, you can cash out and transfer the fiat value into your bank account. But...with the price of Bitcoin rising and the value of fiat falling in comparison...that may be a bit short-sighted. But - you were promised in this tab to tell you what to expect in the way of return on your "mining contract" at Genesis-Mining.
Understand that mining Crypto is a long term process - where you slowly get a return on your investment - your return will depend on the coin you choose to mine and its market price. Before that explosion in Bitcoin prices the return seemed to be about a year - now it's a matter of months. Even with a 30.00 contract you can earn over 5,000 satoshis daily (100,000,000 units in a Bitcoin, yes 100 million) - who knows what that may be valued at in the future. (the five contracts I have with Genesis for the Sha256 contract generate about 42,000 satoshis a day.)
What you can count on at Genesis-Mining is near 100% up-time on your mining rig, great customer service, your choice of coins to mine - and having a long term plan with a stable company in the crypto mining industry. Yes..there are other Bitcoin mining companies and a variety of prices for the Hashpower in their contracts - but the prices are similar and I don't know about their customer service - Genesis I know the customer service and that is why I recommend it.