Ah, well, I wouldn't call it a promise. Bitcoin and Ethereum are good long-term investments. They are, in my opinion, the most secure and risk-free cryptocurrency investment available right now. But if you can manage your profits well, which means you know when to purchase and sell, I believe it's excellent to work on any popular projects. It's impossible to predict the ultimate success or failure of any endeavor, no matter how promising it may seem at the outset.
Nothing is risk-free in crypto, but the top coins are obviously having the edge while the rest are only going to show short term profits but no long term gains.
A popular project does not necessarily mean a profitable project - an investor's interest in a project should be clear, whether they want to be an influencer on the project and make it popular or be discreet and make money.
Listen to Luna. So, all we have to do is maintain a state of constant vigilance while traversing the crypto space. Certainly not a stroll in the park.
One of the many examples of scams and ponzis that run in the industry. I am sure more are also running like that and people are investing in them without the mainstream media reporting about it because these scams run via referral-networks. They will get reported when the tables turn.
This can be prevented by being logical about returns and by doing your own research on how ponzis work.