this is safe or not depend on how we invest our money, did we invest all of money and didnt set trading rule or money management ? even if buy major coins which is relatively safer it could make our money lose as long as we careless about in which price we have to entry. There are alot good altcoin in market , and we could pick one them that will give us profits, but we have to research it before.
The crypto market cannot be secure on its own. This is one of the most speculative markets in the world, how is it supposed to be safe?
It must be dangerous because it is in his nature. Even ordinary investments have a risk, and the crypto market is multiple times, especially altcoins.