It would be a great addition to have handle in/out as default metadata columns for shots.
  1. It could be used to automatically set in/out points for previews/playlists so you can see it with or without the handles
  2. Kitsus OpenPype/Ayon integration is very good but OP expects handles in its metadata. Currently you can create your own metadata column in Kitsu and OP can read it but it's up to each user to name it correctly instead of having it already set by Kitsu
For ease you should also be able to set the handle in/out in the projects preference so each new shot that gets created gets the handle value applied to it by default, so you don't need to add it manually to 400+ shots.
Handles should not be counted into the amount of frames in a shot/sequence/episode/project. It should simply be there as metadata and maybe help to automatically set the in/out point in the player