Well, the trick of Ponzi scheme is that it looks externally exactly like legit financial company - you get investments, you pay dividends, you attract more investments to finance growth - this is how many legit companies work. Without looking inside - whether or not the company has legit activity going on on the inside, whether currently profitable or not - it's impossible to know, externally it looks the same.
What I had in mind is that once you take several rounds of investments (especially from private individuals) and are not profitable, bad faith critics may try to picture you as some kind of Ponzi scheme (trying to repay early investors with late ones, etc.)