This ponzi accusation is the very same accusation that bitcoin had to deal with back in 2010, 2011 when it started out. Every new currency gets accused of being a ponzi, because it is only the early visionaries that see the value. It is very interesting how the roles change. In the start of bitcoin it was the gold bugs that vehemently charged bitcoin for being a ponzi. Now, (6-7 years later) it is the bitcoin (maximalist ?) that are making the charge against the new up-coming digital currencies. Life is funny.