Whether it's right or wrong, college hockey is now merely catching up to where the rest of the college sports world has been for years. It's absolutely about "brand differentiation", which in turn is about money, prestige and image (which all go hand-in-hand).
Whether the BTHC is better than the SL or CCHA or WCHA or Hockey East on the ice is largely irrelevant for conference alignment purposes. In fact, conference alignment in college sports is actually counterintuitive: the most valuable schools are the ones that still provide value *even when they suck on the field/court/ice*. Do you provide a great fan base? Do you have a great TV market? Do you have a national brand name? Have casual sports fans that rarely watch your sport heard of you? Even the most powerful programs in any sport will inevitably have down periods. Anyone can draw fans when they're winning. That's easy. It's the programs that still actually draw fans and viewers during those down periods that are the most valuable ones of all. (That's why Notre Dame football still gets paid a ton of scratch.)
As a result, the strongest conferences are the ones with similarly-situated schools. Now, the Big Ten is quite a bit more than just a new hockey league - in case people have forgotten, it's been in existence for everything else for over 100 years and they are all like-minded academic institutions as a whole (not just sports departments). I see a lot of people on this board blaming Barry Alvarez or Minnesota or whoever else for the BTHC, but the fact of the matter is that they were going to form a league if/when there was a 6th member, just as is the case with every other sport where it has the NCAA auto-bid minimum. The Big Ten is all about branding - whether you like them or not, it's an extremely powerful and valuable brand name (and that's why they've kept it despite having 12 members).
Likewise, the new SL is about those 6 schools branding themselves, too. Perception is reality in college sports. Being in a strong conference is actually more important than being a strong program in today's college sports world (unless you can go it alone like ND football). Is it theoretically harder to win? Maybe, but we've seen in college football, basketball and baseball that long-term success is almost predicated on being in a strong conference top-to-bottom. For instance, it might be easier for the Big East schools to make a BCS bowl right now, but they are clearly worse off financially (which has had long-term effects on recruiting and TV exposure) after losing Miami, VT and BC as it now has a stigma of being behind the other BCS leagues. Maybe you won't see the effects immediately, yet in 5 to 10 years, the results on the ice are going to be tilted toward the new power leagues. Money doesn't guarantee winning, but it does guarantee stability, which is worth a ton in an unstable college sports environment.