> any exploit that gets only gets you memory read/write but not kernelspace code execution That's an odd assumption. There are still a lot of universal tricks

> any exploit that gets only gets you memory read/write but not kernelspace code execution That's an odd assumption. There are still a lot of universal tricks for turning a truly arbitrary R/W primitive into code execution, e.g. just write to the page table. OTOH, this does guard against arbitrary read primitives, which, as you mentioned, is especially useful in post-Spectre days.