"It's great that..."とは「~よかった」という意味です。良いことがあれば、この表現を使うことができます。
例えば、
「休み取れて良かったね!」It's great that you were able to take the day off.
「雨が止んでくれて、ハイキングできて良かった!」It's great that it stopped raining and we were able to go hiking.
「久しぶりに会って良かったね」 It's great that we were able to meet after a long time.