I would love to see this feature too but probably best to not guess how hard something is if you didn't build it. Maybe it requires too much CPU to do it in real time (or enough of the CPU to mess up other things during live recording). As an example, and this is pure speculation on my part... The required ppqn resolution is going to be ~50X higher which is a lot of CPU cycles (1 possible spot per step vs 50 possible spots per step). Or, during recording, the code: "That note came in a little early. Should it be a negative offset or a positive offset on the previous step? First check if there was an event on the previous step... too much recursion..." All of this eats CPU.
Maybe they can drum up a way to store timestamps and defer calculating the offsets until you're back in play mode, who knows. Would love to see it too.