Maybe it's a weird, unusual edge case but maybe not. Lots of people need to keep records of various things for various reasons. In my personal life, I also "print" lots of stuff from various web sites to PDF for record-keeping purposes. This is absolutely routine for me, I do it all the time.

Thankfully, most of the web sites for which I want to do this — banks and other financial institutions, but others also — have easy ways to create printable receipts because they know that people want to do things like this.

And you can disagree, but when I come across some e-commerce site where printing what I want or need to PDF doesn't work because the site just makes a horrible unreadable mess out of it, I think, well here's a set of "web developers" who are just not good at what they do.

(And yes, I fall back to screen shots when I must.)