Well, not only altcoins but Bitcoin, stocks do not give us a guaranteed to get profit in the future, That's why it's recommended to do some research before investing in any altcoins project especially when a bull market is near there is a lot of new projects only want our money without any real development. A project that has good progress according to their roadmap and a good team in the project is worth to invest.
We can't find such things in new projects, so it means that we don't have to invest in them either.
It was not just we do the research, checking their roadmap if is followed or not, or if there is progress on a particular project. In fact, we can't expect Luna to turn into a scam as people never think about it. That is why it was hard to tell if that project is reliable and trustworthy or not, but the most important is that we never invest in a scam project.