I'm Australian and was always told the cover letter was unnecessary, especially if your CV has a bio.
The cover letter was for additional information not covered by the resume - name dropping the manager at the company you know who inspired you to apply, explaining why it appears your changing industries, justifying "overqualifications", mentioning a personal hobby that's relevant to the industry and isn't technical work experience.
Basically the things you plan to bring up in the interview to wow them, you can introduce them while introducing yourself in a cover letter.
But if your resume lines up with the position description, you don't need a cover letter.
Basically I was told a cover letter is necessary when you're a burnt out nurse or teacher applying to be a cashier at kmart to avoid having your resume immediately thrown out.
That said. I've literally never written one, even as a serial industry hopper. If there's no email address to send my resume too, then the system is too auto for a cover letter and they don't want to read it anyway, if there is an email address, just include a few lines of a short cover letter in the body text of the email before attaching your resume.
The US does not use what you call a CV. A resume is something else. For one thing, there is typically no “profile”.
A resume may not even show a complete work history. It is one ( maybe two ) pages and heavily tailored to what makes sense for the particular job. That is what this post is about.