Yes, it's true that altcoins always follow bitcoin. then you are right that it is safer to invest in bitcoin. but there are so many reasons why people buy altcoins. like myself who expect bigger profits from altcoins. namely in short-term trading (scalping). because I feel that altcoins are more suitable for short and medium-term trading because of higher fluctuations so it is easy to profit from scalping results and for the long term bitcoin should be the choice because it has minimal risk and has undoubted potential.