if a feature I want is in the paid product then I assume there's less chance of it being added to the free version. every feature has to go through a process to decide if it's paid or free.
If there's money to be made the possibility that the feature will ever exist at all goes way up. I'd rather have the ability to pay for a feature if I decide I need it than to hope some maintainer gets around to building it for free.
They've said that the feature they put in the premium product are the features they don't want to build or maintain without being paid to do so.
