The pre-made layouts and installed apps offer convenience, especially for beginners. You can do it yourself and spend time, or pay and save time. I think they should add more to the Pro version, maybe even more layouts to choose from. I think convenience and peace of mind are 2 things that should be capitalized on in Linux space.
The other nice thing Pro includes, which users new to Linux might find useful, is the installation support from the team.
It would be interesting to see revenue breakdown, to see how donations compare to the Pro sales. At least percentage-wise.