When you add "indeed" you are just sounding more British, formal and a bit more sophisticated (it's a more middle or upper class way of speaking).
You would not say that to somebody in your family or a good friend.

I don't say that a lot because I think it sounds a bit pretentios... but I might say it for example in an expensive shop, if the shop assistant was extremely helpful and very nice.

On the News they sometimes say it after they interview people, which is a good example of when it might be used.

No need to use this expression as a non-native speaker of English...