> don't waste space on a desk
That has always baffled me. If you're using a computer professionally you have at least two monitors... and even one is as wide as a full sized keyboard or wider.
Not to mention that TKLs tend to also squeeze the arrow keys and the other navigation keys.
You're probably thinking of a 75%, which is a questionable layout, yes. A typical TKL keyboard is spaced like a fullsize, just without the numpad cluster.
Smaller layouts (even 40%) have their advantages in minimizing how much you have to move your hands and fingers but there are tradeoffs (and a learning curve due to the necessary layers in the smallest ones).
I'll see if I can come up with something with more up to date scholarship / better pictures (the work above is effectively but simply illustrated).