Naively these two webhooks sound rather similar. From the somewhat sparse documentation at https://shopify.dev/docs/admin-api/rest/reference/events/webhook, I can see that the message bodies have a different format but I was wondering when exactly these events fire. From some tests I've run it seems that many changes to an order fire orders/updated but not orders/edited. When does orders/edited fire? Is it just for changes to order line items?
I just checked with the orders team and the main difference is that 'orders/edited' is sent when the content of an order changes the value of goods sold (such as when a cross-sell offer is accepted at checkout), and 'orders/updated' changes whenever the order is updated at all (including when an 'orders/edited' webhook is triggered).
I agree that the documentation could be better. I have added this as an item for us to look into.