People have a lot better info than total profitability to answer "can this make money" or not. Financial statements (like this S-1) do their best to separate out how much is being spent to keep customers from how much is spent to acquire them. In lots of cases (including this one) the company has proved that they have a profitable relationship with existing customers, and that they have tolerable-and-dropping costs in acquiring new customers (in this case it looks like they are breaking even on new customers in around 9 months).
There are exceptions and sleight of hand (like when Uber doesn't reveal costs to get drivers, but this is 100% true for formerly-profitable companies too. You could make a much better argument for skipping on those, or by forcing more disclosure in S-1s. But painting broadly based on total profitability is just too simplistic.