Transparent terminals are a feature that they used to have. I've used that feature myself so that I'd be constantly looking at my daughter's happy face rather than the blank background of my many terminals. No utilitarian purpose? Perhaps. But a very real psychological one!
In fact this is valuable enough to people who spend time in terminals that even commercial OSs that you disparage, like OS X, have realized this is a valuable feature to include. So have the providers of other terminals.
But Gnome developers don't see things this way. They have a theory of what is utilitarian for their users, and that is the direction that they pursue. In the process they consistently ignore actual feedback from actual users, and completely devalue the psychological needs of their own users. This is a great attitude if you are designing a jail. Not so great if you are designing something for humans.