We need to distinguish between traditions and Tradition with a capital "T." All churches have traditions. But sacred Tradition is a direct expression of the authority Jesus gave to the apostle Peter and his successors. For over a century there was no New Testament. What was taught was oral Tradition. The faithful, like us today, had to rely on the authority Jesus gave to the leaders of the Church and their successors. It was that authority that eventually compiled the New Testament, discerning which books to include and which not. Whatever the Church teaches, it is bound to fidelity to sacred Tradition and sacred Scripture. This is why it cannot sanction anything it chooses but only that which is in accord with what it has been given: e.g., prohibiting the use of anything but grape wine and wheat bread for the Eucharist.