It started with basic indifference and became a feature.

In the beginning, people were manually receiving and reviewing resumes given to them in person.

This moved online and, for a time, normal humans continued to upload their resumes. Humans continued to review them.

Eventually someone decided they wanted to spam resumes, like someone swiping right on every potential Tinder match, then turning people down later. This spam became problematic, so companies needed a way to automatically filter folks. Extracting info from PDFs is (wasn’t) easy at the time.

Having a from to fill out prevented some spam and let them do keyword searches and following, but more importantly now it gives them two things: It prefilters people who don’t care enough to complete it and add a sight sunk cost bias to folks who are on the fence.