Based on the comments and the article, it seems like Intel is relying on a patched kernel so that the mitigations at the GPU driver stack are no longer necessar

Based on the comments and the article, it seems like Intel is relying on a patched kernel so that the mitigations at the GPU driver stack are no longer necessary. You get security warnings if you try to run the unpatched GPU stack without a patched kernel. If my interpretation is correct, that means as long as you're using an up-to-date, patched kernel with standard mitigations enabled, the extra security layer Intel added is no longer necessary. It could expose another bug not yet covered by patches, though, as the heavy-handed patch probably also prevented more security issues.