Yea, I don't know a whole lot about Vanillacoin, but I'm pretty sure it's just taking a Bitcoin 0 conf transaction and using a locking mechanism (which may or may not have security issues) to just visually credit your account faster. The transactions all still have to be put in a block if you're using a blockchain system...you didn't just gain infinite TPS from nothing. All PoS systems that don't die will eventually switch to deterministic block validation anyway, thus making that 0 time thing irrelevant.
You must be confusing ZeroTime with instantX because your missing allot here and barely touching the basics of the technology. Also "visually crediting" is inaccurate, it is a core layer consensus based confirmation. I often perform ~5100 TPS stress tests with no back-log. I see no reason to switch to deterministic block validation since this is well under capacity. 
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