The answer would be, Madam Chair, flexibility.
Amending IRPA to provide a different duration, amending IRPA to do other things that are proposed in the bill, allowing for an insurance provider or reducing the minimum income, are all sort of programmatic requirements. The only one I would see as worthwhile to consider putting into the act or the regulations would be the duration of the visa, but I think the Canadian immigration system would benefit from the use of ministerial instructions to adjust or change something like the duration of a visa without having to amend the act. I think there are more fundamental things that would be done in the legislation.
I would also agree with caution about the use of ministerial instructions for many things and that, when ministerial instructions are used, the government has an obligation to report to Parliament at least annually on the use of ministerial instructions.