Questions about educational qualifications turn up in all sorts of studies there days. I've conducted street interviews on behalf of lots of organisations where they've been included. (In non-Covid times I work as a contractor for a firm specialising in travel surveys).
With some surveys, such as one for the Medical Research Council, asking people about their usage of the Cambridge Guided Busway, their inclusion doesn't seem to be out of place. (It might surprise some people though to learn that the vast majority of users of the Cambridge Guided Busway are graduates, with the majority of them holding higher degrees!)
With other surveys, such questions are included to ensure that there can't be criticism of a study because of built-in bias. e.g. if a medical survey is carried out solely using people who've got a degree-level of education, the chances are higher that they're generally following healthier diets and lifestyles than a true cross-section of the population would be, as it's known that there's a strong correlation between levels of education and general levels of health (with people with masters degrees and doctorates tending to live far longer than people with no educational qualifications at all).