I don't consider that one truly 1:2, but I do consider it one of the few transfers that can reasonably be considered at one to slightly greater than one if the HH points are used well. (Assuming a large enough conversion that the $25 fee becomes trivial.)

Another one that is sort of like a 1 to greater-than-one transfer is the Marriott Travel Package award. If you accept the Marriott 7-night hotel award as a fair value, you are effectively swapping 120k MR for 120k airline miles, which most folks would consider a 25-50% gain in value.

SPG to air miles is a losing proposition unless it's a small amount done to liberate orphaned miles. Even post-devaluation, SPG points are worth more as hotel stays. Unless your "liberation" is to hit a big airline award, you probably won't get the 1.25 miles per point. The only one of these I've ever done is 5k SPG-Amtrak-YX to redeem a one-way award. I figure I roughly got 3 cents per mile/point out of that, which is so-so for a Starpoint but great for the other 10,000 air miles that were liberated.

(All of my numbers assume that an airline mile that I receive today is worth about 1.5 cents in today's dollars.)