The only reason they are that tall is when you encounter them in combat they stand out. Its kind of like important characters in some MMORPGs, they aren’t canonically 7-9ft tall. But they’re enlarged in specialized sections of the game so they tower over their minions/subordinates for them to stand out and be easily identified.

Its just weird that named patrons in a bar have their heroic combat sizes. They could probably put an adjustment in so they appear normal sized there.