The reason I said this is because many people tend to invest in crypto currencies and have no other source of income. If they fully depend on their crypto investments, they will end up using everything that they have already invested, and they will be the ones to end up losing.
The biggest problem is that you can't sit out losses in a situation like this because you are dependent on the money.
You only need to look at the Bitcoin market. For example, if you invested 60k in BTC at the end of the last bull run, you now have a (very large) loss for 2 years. If you are dependent on the money during this time, you will have to sell the BTCs again at a significant loss.
However, if you invest money that you don't actually need, you can skip the 2 years and wait until the prices improve again ... and even if you start with 60k, you are currently making a positive exit.
Patience and time is everything ...