In any exchange with the US, any question asked was responded to with, "That's a great question!".
It was probably just filler but definitely came across as incredibly patronising to our ears.
Is this a time-filler like “that’s a great question” for extreme people pleasers? Or just an agreeability signal? To me it makes the answerer seem overeager to share. It could just be regional culture.
Personally, I use the phrase often as a Senior IC in a way that makes it clear it t is not filler. I also use phrases such as, "Hell if I know, let's google it and find out together."