Shockingly, this is actually how banks work in reality. In the United States, the reserve requirement, or the percentage of net deposits banks are actually required to keep in liquid financial instruments on hand, is generally 10% for most banks. This means that if a bank has net deposits of a billion dollars, it needs to only keep 100 million on hand at any given time.
This, thus, requires anyone holding fiat currencies to have extreme trust that their government will manage their money supply responsibly, and not make poor financial decisions that will severely devalue the currency they hold. This compounds with the trust one must hold in the banks in which one deposits their fiat currency, to create an ultimate monetary system that has multiple points of very real possible failure, as history has shown time and again.
You can trade immediately as much as you want by sending a wire (only applicable for US customers) to your account following their deposit instructions. There’s a $10 fee for this that GDAX charges, on top of whatever your bank charges to send wire transactions. This is the fastest method to deposit any amount of money you want and trade immediately with no limits, but not the cheapest.
How assets are valued is a changing model, and the quoted market cap of a coin is an excellent tool for benchmarking but can be misleading. Chris Burniske wrote about this on Medium. As currency use increases and utility tokens bring products to market, the economic models will be tested and as such valuation models will change. This could go either way; assets could be either under or overvalued. I believe that currencies are undervalued, and utility tokens are overvalued, hence my preference for investing in coins over tokens.
Transaction volume: in order to determine whether a cryptocurrency is actually being used, you can take a look at its transaction volume. In the case of Ethereum, its transaction volume per day is about 500,000 ETH. Historically, this is a number that is increasing and as long as this upward trend continues this reaffirms the long-term viability of holding Ethereum in our portfolio.
Virtual currencies, including bitcoin, experience significant price volatility. Fluctuations in the underlying virtual currency's value between the time you place a trade for a virtual currency futures contract and the time you attempt to liquidate it will affect the value of your futures contract and the potential profit and losses related to it. Investors must be very cautious and monitor any investment that they make.