Dedicated PCIe or memory-attached inference units will continue to exist, and will continue to do the heavy lifting, but an ISA extension provides latencies any external unit would have trouble matching. You can, with some work, extract some decent throughput with CPUs alone, with a large enough CPU you can use for non-AI jobs the rest of the time. There was a nice writeup not that long ago here on HN describing the flags and the reasoning behind them to use on that specific machine.

Funny thing, I can't find the article.