Well obviously it's not for coding, but I understand the one you're replying to perfectly. And I think there are hordes of developpers out there coding daily on their MBP. Which are now sort of left alone. Anecdote, though I doubt I'll be the only one for which the lack of F keys is a showstopper - also see other HN comments: after about 5 years on a Dell I was thingking maybe this year to go back to a MBP (even though my last one lasted only 3 years) but seeing I spend a lot of time debugging, which translates to repeatedly hitting F-keys which is burnt into muscle memory, it's just not going to happen. Even if I'd learn to do it with that bar thingie, it's a bit of a waste of time since going back to any other machine the bar isn't there.
Coders don't just write code (no, you don't need F keys for that and yes your hands kan stay on the home row) they also debug it (for which the environments I, and seemingly others, use, assigned the F keys many many years ago)