If the value of Bitcoin goes down below the cost of digging, people may not be able to start mining anymore but will buy back Bitcoins, which results in loss of diggers, increased transaction fees.

If I have my money on coinbase and they get hacked, does their insurance policy cover my loss?

U.S. Customers
Coinbase stores all customer fiat currency (government-issued currency) in, custodial bank accounts, or in U.S. Treasuries. 

Non-U.S. Customers
Coinbase stores all customer fiat currency (government-issued currency) in segregated, custodial bank accounts. 

Cash balances held in your Coinbase accounts belong to you - not Coinbase. 

If you are a United States resident, your Coinbase USD Wallet is covered by FDIC insurance, up to a maximum of $250,000.

In coin trading, you are your only enemy. There are no rules in this arena, only you facing you, and you are both winner and loser.
People may think that they are fighting with the market, other investors, or those scammers shark that always have their eyes on your money. In fact, you are fighting against yourself. You are the one who made the decision. You can decide yourself to lose or win, trust me.

As human nature, we all want to make a bunches and make it fast; too much temptation that incites us to gamble with our account.
In the end, only you can chase off the temptation to follow the plan.