im viewing this from a churning point of view, so business travelers will obviously be in a different scenario.

my feeling is, if you look at how much Aeroplan it costs to go on a trip, and how much SPG it costs to cover the hotel on the trip, and then compare that demand against the supply side, it is generally easier to get enough Aeroplan pts, as opposed to enough SPG.

if i decide to just pay for the hotels on trips and pool all my pts into Aeroplan to go on more frequent mini RTWs, then i can see why i may want to do this. i can see how that could make sense, since the out of pocket for hotel is more reasonable than the mini RTW in J costs. so that's one scenario at least where you'd want to go from SPG to AP