1; Trading is risky that it can empty your savings overnight but when lucky with good allocated strategies, you can be get rich overnight or probably in Short term. This means you are at the pool of gambling with less chances if at all you will make it a success.
2; Investment has zero risk but demands your patient to get you rich or successful probably in a long term.
Let them decide and make wise or foolish decisions of themselves.
Only a fool will put in all their savings into trading because trading is so risky that even before you want to venture into it, you have also witnessed how the market keep fluctuating and you know that it will require a deep knowledge to understand how to tackle the market before you start trading and even after you start, you don't even have to carry all your savings and deposit to the exchange. That's why I said only fools will allow trading empty their savings because they need not be told about crypto volatility. If maybe some have $3000 in their savings and started trading today and deposited all the $3000, that means the person is just a fool. They must test with small amount first continuously first, it's the results that will determine if they should invest more or not.
Even investment has a risk too, the risk is not totally zero like you said but it's more considerable than trading. If you are investing into alt coins, then you are even at a high risk too but to be successful in both trading and investing, you must have a knowledge of how to manage the risks that are involved.