For some people, it's just more comfortable. I'm probably just as productive on a trip with my 16" MBP, but I still feel some sort of relief when I sit back down on my multi-monitor setup at home.

"I like it more" is a good-enough reason to do it!

Consider another example--I sleep alone on a king-size bed. If I swapped it for a queen bed, I bet it wouldn't even show up in any sort "measurably improved" metric: Time to fall asleep, total time slept, time to wake up, maybe trying to measure physical fitness numbers, etc.

But I still prefer the king bed. Maybe some people wouldn't care, and would rather save the space/money, and that's totally fine too.