The important part is that she’s still officially a member of Congress. People voted for her to represent their interests. If she’s no longer able to fulfill that duty she should have stepped down and let someone else do it. As it stands she and her staff are still collecting salaries paid by the American people. It’s also if interest because of the general tend of geritocracy - our elected officials are really old, and it calls into question the decisions they’re making and their ability to lead.
Lame duck representatives still have the power and duty to vote on legislation!