Then you have to deal with bezels and multiple hook ups and power hook ups, one 40" 4k display simplifies everything, and you're going to need some scaling at 27", it's still going to give you plenty of room, but if you're doing like video editing, you can have a 1080p preview windows and an ungodly amount of space for tracks and your clip folder.
I've run multi monitor since the days I had 3 CRTs on my desk and a 4th on a shelf. The 40" 4k is way better than any multi monitor config I've come up with. That includes having over $1000 worth of VESA arms to try and get the config I want.
The 1 40" 4k is MUCH better for productivity for my work load (software development) than 4 24" 1080 monitors.