Completely autonomous electronics?

Hi all.

The usual way to have a RepRap know what to print, is to have it attached to a PC.
Even if you are printing from an SD card, the PC is still here to order the print.

What about a completely stand-alone setup - no PC or RPi or other purchase-only device to give orders?
Was it ever done?
If so, what problems were there?
If not, why not?

I was making my own electronics for my Prussa i2, so i designed them to be autonomous from the start.
The basic design is similar to Sanguinololu - ATMega644 core.
The main difference is the addition of buttons and a screen.
The files to print are stored on an SD card.
Runs a butchered variant of Sprinter firmware (Arduinoless, bootloader updates firmware from a file on the card)

That's what it looks like, in a crude prototype:


Simple four-button interface for all controls, simple menu-based LCD.


You can move the axes and toggle the heater:


You can select the file for printing:


And then have a status as it goes:


Pause, abort, all the conveniences.

Now, the purpose of me telling this is - is it worth making and publishing, or should it stay a private project?
Is anyone interested in having electronics like that?
So far it suffices for me, but for public use it'll have to be cleaned up.

I was planning to etch a dedicated PCB for it, to free up the breadboard:


A version of it to use the popular Polou boards and like would be necessary.
The firmware also needs refining to be presentable.

Would all this be worth the trouble, or is there a reason no one does it this way?