In this particular case the coal was being shipped from Canada, which benefits Canada, who happens to claim to own much of the Arctic. Presumably ships carrying Canadian cargo would be cleared to use this route, and legally be required to seek such clearance in order to be cleared to leave Canadian port. Other ships which do not leave from, refuel at, or stop on Canadian land, would presumably be asked to seek permission to pass through what most of the world considers international waters. There are only certain countries that would even want to, but it would obviously be useful for China, Japan and Korea to use this route for shipments to Europe.
Eventually someone will take the route without permission, and then Canada will need to figure out to what extent they can assert their claimed ownership of the Arctic.
Should Canada succeed in their claims internationally, it may be a good opportunity for other countries to make use of the new doctrine as well. For example Somalia has long claimed that ships going through the Suez canal are passing through their territory, and other nations claim that these are international waters not subject to Somalian boarding for inspection and collection of fees (which other countries call piracy). It will be interesting to see if Canada prevails in its Arctic claims, while maintaining Somalia has no similar claims to control of what they consider national waters, which don't extend anywhere nearly as far from land as Canada is claiming here.