Their marketing has got the phase change physics wrong though. Water is not a good substance to try to make an analogy with GST in this case. Ice is crystalline. liquids are not either crystalline or amorphous. There's no amorphous phase of water analogous to the amorphous phase of GST. The phase change in GST that represents a 0 or 1 is between a crystalline solid phase and an amorphous glass solid phase. Shrinking the bit cell does not make life easier either, certainly not the "slam dunk" they portray. There are thermal management and materials issues that are challenging to say the least as the bit cell reduces.