A full fat processor instead of a mobile, less ram,a real keyboard and mouse your also not making best use of the company's capital - for the relative performance mac books are over priced
Just in general: I've always found it easier to work on my laptop.
I can walk around, go to meetings, sit on different floors, sit on couches, work from home and still be developing the same as I would at my desk.
All I'm trying to say is: Slightly faster builds on a powerful machine, or flexibility and consistency on a laptop. This might just be a matter of preference, and ideally companies should accommodate either preference.
Fuck, I also have an extrenal keyboard and mouse - of course I do! That goes without saying! (all company-paid)
The reason why I use a mac is because everything I build is deployed on Linux. Coding on a WIndows laptop means I wouldn't be able to compile anything, and coding on an Ubuntu laptop...well...I still like having a first world OS experience.
OSX is a fantastic development machine. Most developers use it. It completely fits all my needs and is provided for me by employer so that I can be happy and productive and effective. Which, as you remember, was the original criticism. That Amazon DOESN'T do that.
And that's not counting the H&S aspect RSI is not fun