It's a pain to keep to computers in sync with one another, set up exactly how you want, etc.
I have two laptops, as well.
2016 MBP w/Touch Bar (full specs)
Dell XPS 9560 (full specs), runs Windows 10
At home I have a Dell UP3216Q (32" 4K display)
and a pair of external keyboards and mice (a separate pair for each laptop)
These odds of needing a full spec'd machine are also small but still possible.
Either way I guess I'm saying that an opportunity cost of ~$5,000 is significant.
I don't use a laptop a LOT, but it's super nice for when I need it. So I use a laptop as my main PC.