Cause you are chatting in a sitting position. Of course, my one grandfather made my grandmothers - she was 4'6" (and I think I'm giving her a little height-she came up to my chest when I was 12). There are, literally, thousands of different kinds - many people, I think, back in my grandparents "first telephone" days, made their own. Later on, they started manufacturing them in more standard ways - most had a back to the seat (the later ones - though not all), and instead of the little open-desk thingie, they made a slot underneath. (for the phone book). I've actually only seen, personally, one with the desk top - and even that one was a little different than the one you have. My grandfather, I think, used the pattern from a kids desk and scaled it down - my dad says my grandmother used to complain when she had to talk to the doctor.

(she used to complain about her feet to the doctor - they used to swell terribly).
This conversation brings fond memories. Us kids used to bug my very short grandmother, and she'd get mad and chase us with her broom. God help us if it connected. (she'd cut you off at the knees)
Beth