I think that her most important duty and responsibility for now is:
1. as a woman - bringing up the children,
2. as a Princess Consort - bringing up the heir, which leads to the point 1.
And I think that not attending the celebrations by Princess Consort of Monaco, when the reigning Prince was there, was far smaller faux pas than sending the wife of the youngest son of the Queen (not having even the princely title) alone by the British monarchy.
1. as a woman - bringing up the children,
2. as a Princess Consort - bringing up the heir, which leads to the point 1.
And I think that not attending the celebrations by Princess Consort of Monaco, when the reigning Prince was there, was far smaller faux pas than sending the wife of the youngest son of the Queen (not having even the princely title) alone by the British monarchy.