I wonder who will ever use it and for what.
The PIC32 one is more limited as it only exposes 4 bytes to the external bus interface when used in parallel slave mode. The Sitara exposes a whole block of RAM for that.
Some ideas came to mind:
* A graphics processor for some retrocomputing project.
* An I/O coprocessor for a modern PC, combined with the WCH PCIe to parallel interface chip.
* A heterogeneous multiprocessing system.