I would think that in most cases a role that is responsible for X would already include an accountability that X meet a certain standard. Approving other changes seems implicit in that accountability to me, especially as the person holding the role would presumably want to approve changes made by others. However, I suppose if such an accountability is not clearly implicit in the current role description, or if there is any kind of tension around the task, then it makes sense to add it.
I'm kind of wondering what would trigger this question. Is the person holding the role not making approving changes a priority, creating a backlog? Does that person perhaps feel that such supervision and approval is extra work that is not included in their compensation package or that is interfering with their other priorities? Is someone else trying to do these tasks without having the clear authority to do them?
As always, my guess is that things need to be added only as they are needed to resolve a tension, not to try to meet some idealized standard of perfect role description.
I'm curious to know how others see this.