Pain can be efficient or counterproductive depending on the individual. The threat or pain is usually more efficient than the pain itself.
Your "let's be pal" approach is not far from the KUBARK's recommendations, but it is not incompatible with coercitive methods: On the contrary several of these consist in putting the interrogatee in a state where the interrogator is perceived as a reassuring presence.
Min/max focused #ttrpg players engaging with campaigns where the Bard single-handedly wins a fight by convincing all enemies to just leave by role playing an adorable bunny with very fluffy ears; before their ultra fine tuned theory crafted mega build even gets their turn.
On a completely unrelated note, before I even started with TTRPGs I've played a PC game Neverwinter Nights 2. One of the first quests was to get rid of some lizardfolk in a dungeon. I've went there and convinced them to flee which awarded me 100exp. I was pleased. On my next playthrough I slaughtered them all and netted something around 500exp in total. I was not amused.