In large scale datacenters, you can 'waste' a lot of disk space and processing power running graphical interfaces. In these cases, gong 'headless' makes a lot of sense.
On a personal level, I enjoy terminals for their speed (4-5 words in a single command can often replace 10-20 clicks), and use them to script re-occurring tedious processes.
There are definitely cases where a GUI makes more sense. It is a lot faster, for example, to select several files in a folder and copy them somewhere else using a GUI. GUIs can also offer a better visualization of data in terms of charts and graphs, and that can be useful for monitoring. GUIs are also often better for multitasking, as you can have multiple things on screen at the same time.
I don't think either are going anywhere, nor see them as redundant. They are different tools with different pros and cons.