What are all those scripts for?
Well, some are mostly internal use unless you want to edit or add subtitle files yourself. The most commonly-used ones would be to resync the subtitles against a non-GOUT-synced source (i.e. Puggo or Negative1), or to alter the existing subtitles to go with a preservation without burnt-in alien subs, resize them if you have a big projector screen and the default size is too big, etc. It’s all in the README.
EDIT: Although it’s not frequently used as such, this is designed as a “supply-side” project–the idea being that the people who make preservations use this project to ensure their preservations have global reach–and for everyone else, the “consumer-side”, it just works out of the box. So it tends to have lots of fiddly technical options, for the preservation-makers. I don’t really expect your average person to make much use of them.