I think the comparison to a desktop computer is a fair one.|
Just consider this: I set up a virtual machine running Ubuntu as my cross-compilation environment within less than 30 minutes (and you could do that even faster if you take preconfigured images from the web, or if you already have a linux installation running). Here I spent 30 minutes that I wouldn't have had to on the Banana Pi.
However, now I can compile a kernel within minutes (depending on the system's cpu) as opposed to 2 hours. You might still think it's easier to do this on your BPi if you need to compile the kernel only once. But as soon as you look into compiling the kernel more than once, e.g. when you update your kernel sources, etc., then you really reach a point where in my opinion it is really easier (not only in terms of time) to do this on a desktop machine.