Hey @evnttr 
, appreciate the follow up here. As a general rule, we do only approve read_users access to custom apps for certain merchant plans (Plus would be one of these though). I do know there have been some exceptions to this rule for public apps on a case by case basis, but these are handled through direct outreach by our product and partnership teams (invite only).
Hope this helps clarify things, let me know if I can help out any further at all.