-(으)니까 supplies the reason and 오다 the coming: 이젠 근처에 안 사니까 올 일이 없어서 'I don't live nearby any more, so I've no reason to come', 혹시 모르니까 올 수 있는 분들은 와주세요 'just in case, anyone who can make it please come'. The -(으)ㄹ 테니까 variant attaches a promise to an invitation: 내가 예약할 테니까 와 'I'll book it, so come'. Note that -다 보니까 in one line is a different fixed pattern, 'as it turned out over time'.