I was offered a large external monitor by my employer, but I turned it down because I didn't want to get used to it, and working in different locations is too critical to my workflow. But I'd love to see how people with more than 2 external displays are actually using them enough to justify the space and cost (not being facetious, I really would).
1. Web Conferencing Content
2. Web Conferencing participants video
3. Screen where I multitask in parallel
4. VDI session to a customer's environment for tests
My friend uses 5 monitors, and I would too if I wasn't mandated to use an iJoke computer at work.
Teams, browser and IDE mandate a minimum of 3 displays.
First - dedicated to personal Chrome profile, Discord, etc.
Second - dedicated to screen share - VS Code, terminal, JIRA, etc.
Third - Work Chrome Profile for email/JIRA/web browsing, note-taking (shoutout to https://obsidian.md), Slack.
I could certainly get by with fewer monitors, and do so when I am mobile, but I really enjoy the screen real estate when at my desk at home.