its not an alt coin. BU is an implemtnation of bitcoin. it allows emergent consensus on blocksize. If a majority of hashpower forms consensus and some miners try to make a minority fork, the majority fork will be BU but its not seperat right now. you cannot buy "BTU" except as bogus futures contracts.
I remember people saying the exact same things about Bitcoin XT two years ago, and if I remember correctly, you were one of them. Folks on this board were incredibly adamant about making the point that their fork wasn't just another altcoin, but in reality that's exactly what it became.
This is just another such project hoping to capitalize off the success of bitcoin. It even borrowed its name.
I'm not saying BTC will be the digital currency that most people settle on in the future. Perhaps increasing block size isn't such a bad idea. But this is clearly just another attempt to hijack bitcoin's fame. One of many past and many to come.
*I also forgot about Bitcoin Classic...
https://en.wikipedia.org/wiki/Bitcoin_Classic