There are a lot more ways one can use OpenCL than CUDA. NVIDIA GPUs will run OpenCL. Intel CPUs and FPGAs will run OpenCL. Using pocl just about every CPU will run OpenCL.
One of the accelerators on the BeagleY-AI single-board computer runs OpenCL. I have one, and this little $80 card gets 50 32-bit GFLOPS in clpeak!
The reason I ask is twofold:
pocl
just about every CPU will run OpenCL.clpeak
!