I like the SMU invite for a lot of reasons. It seems odd at first blush having a lone outpost that far away the west coast from both SMU's perspective and that of other Pac-12 schools, and travel is going to be a pain, but it's close to the mountain state programs and, in a way, may help keep them around, and D/FW is about as good as it gets in terms of easy travel and accommodations. It also isn't much different from Boise State having been willing to play in the Big East, West Virginia playing in the Big 12, or SMU previously playing schools like South Florida, Coastal Carolina, and various others in the AAC. Even less ridiculous in some ways.
More generally, I'm firm with my belief that you can't just look at a G of 5 program and its lack of attendance and interest in a vacuum. SMU is expanding its stadium, has a shitload of money, and is the only real university in Dallas proper, which is a top-5 recruiting area and up there with just about anywhere. If TCU could step up to P5 and do pretty well, as it has done, I don't see why SMU couldn't do so over the next decade or so. It isn't going to displace UT or A&M among the attached, but they'll sell seats and get people to tune in if they are able to run top-25 types of teams out there, which I think they can do pretty often.
SDSU is a no-brainer like it long has been.