In Which Cases Is Linux Bootcamp justified? To be on the safe side, I know I will be doing a Windows Bootcamp because there are some programs in my field that don't have a Mac-specific version out yet.

But for, say developers, are there any reasons behind having Linux Bootcamp on your Mac? 

Or are the Terminal apps identical in all respects? For command-line users. In that case it might be completely superfluous. Right?
"Terminal"-apps on macOS (I put that in quotes because technically they haven't got anything to do with Terminal.app, but merely being command line programs) are not in general identical to macOS apps. However most are very similar. 

This stems from the fact that macOS can trace many of its standard command line tools to FreeBSD whereas Linux inherits them from GNU. In practical terms, you'll quickly learn the minor differences between the two. It is also possible to install the actual GNU command line tools on macOS using HomeBrew, and then they are identical.

Does this mean that there are no reasons at all for running Linux in BootCamp? - No, not really. There's still advantages to BootCamp when you for example want to run some performance demanding games, when you want to use Linux specific device drivers for built-in hardware, and other things. BootCamp essentially takes over the whole computer - leaving none of macOS running. 

However just the fact that you want to run a program that doesn't have a Mac-specific version doesn't mean that you have to run BootCamp - no matter if it is Windows or Linux. In those cases, many use virtualization to keep running the macOS desktop while running some apps in Windows or Linux at the same time in seperate windows. For example you can use VMware Fusion, Parallels Desktop or the free VirtualBox to run Windows/Linux on top of macOS.