The meaning and usage here is similar to "well, thank you", "well, yes", etc. It expresses a slight degree of surprise. The first example sentence you have given has become somewhat of a fixed expression in modern English (often used half-jokingly to express modesty, but also surprise at the compliment given). I don't hear the second very often.
I don't think it is to do with regional or geographic variation, so much as age or register. It's quite old-fashioned - almost quaint. You don't hear young people say it except in a lighthearted or frivolous way, perhaps when they are mimicking someone who does say it.