Bitcoin is the best as well as most profitable and this fact will only understandable by realising that altcoins can be scam but bitcoin does not show any property of scam project yet.
Bitcoin has been around for 15 years seems to be too much if this was all a scam, right?
At this point if someone still does not believe the legitimacy of bitcoin then they are nothing but a hopeless case. Bitcoin has proved itself from time to time again that it does give people advantages by investments. Sure there are still risks but mostly the benefits it brings is more than worthy of the risks you are going to take.