Even without considering laptops, I can already imagine quite a few circumstances where someone might want monitors of differing DPIs. I’ve actually thought sometimes of getting a smaller monitor I can have off to the side that I display a browser window containing mostly text on when I’m playing videogames or working in something like Blender or Aseprite; yknow, for referencing a guide, wiki, or manual or something. I don’t even have a super high desire for a multi-monitor setup outside of that.
If your monitors are different DPIs then multimonitor X11 is awful.
If you’re questioning why anyone would have monitors with different DPIs remember that laptops exist.
Even without considering laptops, I can already imagine quite a few circumstances where someone might want monitors of differing DPIs. I’ve actually thought sometimes of getting a smaller monitor I can have off to the side that I display a browser window containing mostly text on when I’m playing videogames or working in something like Blender or Aseprite; yknow, for referencing a guide, wiki, or manual or something. I don’t even have a super high desire for a multi-monitor setup outside of that.