No European has ever used an Europass CV to apply to a job.

I see that some grad schools in Europe want a Europass CV. Is this more or less what it is meant for, or are there other niche use-cases?

At least one did. Source: interviewed him.

I'm recruiting for an outsourced team in Portugal at the moment. They include photos on their CVs. Date of birth and marital status is pretty much standard in Norway as well.

I think that's mainly because of past conventions, and the lack of sharing current expectations. A company could refer to Europass in their job description, and also offer a filled out CV template that only lists personal information that is expected to be shared. Or are CVs which do not include photos still considered incomplete or less desirable by the recruiters you know?

You should only put a picture if you have a very good looking photo specifically for this purpose and if you are in a customer facing role. Otherwise it's likely to do more harm than good.

I've noticed the same trend as well. Different parts of Europe & South America its fairly common to include a photo of yourself on the topleft corner