This sort of thing is not uncommon in the embedded space. Lots of devices basically built on a DSP with a tiny arm core tacked on the handle application logic
There were many X terminals running off nothing but a Texas 34010, which was a very DSP-like CPU that ended up in a lot of high-end graphics acceleration boards for PCs and Macs (and Unix workstations).
The fact it could boot up an X server is quite extraordinary.
I wonder what the VideoCore looks like to the programmer.
Since it was designed explicitly to serve that purpose, I'm not sure why it's 'extraordinary'.
Disclaimer: I spent time at a 34010 X terminal shop.
I never imagined that. Now I'm surprised there were no desktop computers based on it. I knew the Intel 860 and 960 were designed as computers and got some usage as that, but I never knew the 34010 and 34020 were like that.