I haven't done the math (lately) as our esteemed colleagues do, but when I did some years ago, it seemed to me within the realm of reasonable to transfer a bundle of Choice points to Southwest (at others' suggestion that it's the best transfer value if we're up against a wall) but not to earn directly per stay into RR. With the stipulation that I then use the slippery RR points on a low-(RR points)-redemption price.