well 2 things:

1) 1.5 TFLOPS is already less than the GPUs in most current phones. Like you're not exactly talking a big number here. You're talking 14 year old graphics (when desktop GPUs crossed the 1TFLOP mark)

2) And, this is the bigger issue, this AMX unit only does matrix multiplies. I'd be fascinated to see someone create a 3d renderer with only matrix multiplication. I'm sure it's possible but this 1.5 tflops ain't remotely comparable to a GPU's 1.5 tflops. Like if you tried to do "traditional" pixel shader rendering code on this unit you'd instantly be cutting that 1.5 tflops to 1/16th the performance - you're now at a theoretical peak of a mere 93 gflops of GPU-comparable performance.