In short, yes, many, but no all, of the things the terminal can do can be simulated with an application of some type...
But trust, many times, it's easier to use the terminal then digging through hidden panes for a particular setting.
Also, for many UNIX ports, install itself depends upon terminal access...period. Unless you have BBEdit 6.5 (shell worksheets are a god-send), then master the Terminal as though it were your second child.
The Console is a rather simple application which displays system-level error-messages and warnings.
Very useful for debugging annoying, and poorly written Cocoa applications...as well as some daemon's ( like FMPro server ).
In short, learn them, love them, live them.