The free and the paid version of course are different.
FE obviously needed the distillation abilities of the Adobe creation suite, probably as a part of his generating manuals and application notes for his job. The reader part is just to test the output, and, being part of the suite, obviously does not have all of the bloat associated with having an updater, checking for updates and such, just the whole cut down core only. The suite relies on the developer being notified, and then updating the whole suite.