JR Mini 3 day pass on klook

my wife and I are going to osaka nara and kyoto in a few days and we were torn between just buying the icoca or buying the jr mini 3 day pass however im confused because of some limitations. Say im coming from dotunburi and want to go to nara deer park using google suggestions best route, can i use jr mini pass on kintetsu nara line? or if i want to go to kyoto in another day and want to take Sakaisuji line. is it still valid? because i read that jr is only usable on jr lines. Thank you