According to the Covenant's proponents, one of its advantages will be that it will ease ecumenical relations.
This is no doubt true at a worldwide level, though it carries a heavy price. It is true because representative committees often find themselves at a disadvantage in discussions with other denominations. Representatives of Roman Catholic and Orthodox churches are able to state clearly where their denominations stand on particular issues. Anglicans in these dialogues would be able to speak with comparable confidence if Anglicanism had clearly stated positions on the relevant issues.
The price is that clearly stated positions will nearly always misrepresent what Anglicans actually believe because we do not all hold the same views. A set of tidy statements declaring what Anglicans believe would only be a true representation of Anglicanism if it were to become a confessional church.
At a local level the Covenant would not help ecumenism at all; on the contrary it would probably often hinder it because it would give other provinces the means to lodge formal objections to ecumenical initiatives.
It often happens that another denomination's relationship with Anglicans is good in one part of the world but bad in another. For an Anglican church to work more closely with another denomination may be a constructive initiative in one place while elsewhere, in another part of the world where circumstances are very different, the prospect of cooperating with that denomination seems utterly abhorrent. If the Covenant comes into force, it will be easily available to block ecumenical moves in this way, and it would be surprising if it was never used.