what is risk in Crypto

With CMC Markets you can trade bitcoin and ethereum via a spread bet or CFD account. This means you are exposed to slightly different risks compared to when buying these cryptocurrencies outright. 
They are high-risk speculative products: with spread betting and CFD trading you only need to deposit a percentage of the value of a trade to open a position. Profits and losses are based on the full value of the trade. The volatility of cryptocurrencies, combined with trading on margin, could lead to significant losses.
They can be affected by gapping: market volatility can cause prices to move from one level to another without actually passing through the level in between. Gapping (or slippage) usually occurs during periods of high market volatility. As a result, your stop-loss could be executed at a worse level than you had requested. This can worsen losses if the market moves against you.
Charges may be greater than with other asset classes: you should review all costs involved before you trade. Charges may be higher when spread betting or trading CFD cryptocurrencies. The likelihood of making a profit versus the impact of these fees should be considered.
Pricing variations: compared with currencies, there can be significant variations in the pricing of cryptocurrencies used to determine the value of spread bet and CFD positions.