Screen space.

I work in tech doing performance, memory management, and developer workflow tooling and automation for a large 3D Rendering/Creation tool.

Being able to throw a long setup doc, or a large class file on a 4k portrait monitor allows me to read things through with a ton of context and far less scrolling.

It's also useful for putting two window tiles that have related content, or one is a reference content.

I currently have a tie-fighter monitor setup (2x4k portrait on either side of a ultrawide) and will put comms and email/calendar on my left monitor, core work in the center, and overflow reference/research on the right.

It's less hectic for personal use, but I still use all the space.