For that I feel more secure to invest in dibitcoin only, especially with a long period of time. Because we know that no one is able to stop bitcoin. It's different if we invest in altcoin where someone can make the coins to ashes. If I were going to invest in altcoin, surely those were the best coins and would not hold them for a long time. I have also been trapped in a ponzi scheme for that I always ensure security for my investment.