The big problem is that free version is so good that your could expect other companies to charge for it more than 100$ for it. This makes the pro version look like it has not that much value in it, and that is OK, use the free one if you don't need the rest.
However, for the pro version there are a lot of new features planned both small and major ones, so I can assure you you will be very happy that you bought the pro version on time.
For example here is the list for very next improvements:
- Setting text size
White/dark theme for plugin and export
PNG export
Custom presets or saving default state
Netflix preset