It's interesting that the article calls into question monetroization because they won't be making a significant amount of money given the team size.
Heading towards cash flow positive should always be an aim, I don't get how people think that not charging for something now will magically make the same people want to pay for it later, if anything the pricing structure should be there from the start, let users know that you have some value on offer with your service.
If you can convey that the upgrade adds value, and they have budget (or can maneuver the politics of getting budget), then they'll pay. The fact that the upgrade adds value (or not) is actually secondary in many cases.
Heading towards cash flow positive should always be an aim, I don't get how people think that not charging for something now will magically make the same people want to pay for it later, if anything the pricing structure should be there from the start, let users know that you have some value on offer with your service.