I'm not familiar with nxt assets, I was referring to POS in general. Having ANY POS whatsoever discourages spending and thus kills adoption. Having no POS encourages spending, because your money will be worth less than it is tommorow. Alt-coins are supposed to be just that, coins, a currency. If you dont want your currency to devalue you invest it somewhere(get interest at a bank, buy stocks w/e), you shouldn't expect the act of holding to be rewarded.
Please explain.
I think more correct assessment is that by holding PoS coins you are eligible to receive interest, while PoW coins don't give you any interest explicitly, but rather from scarcity/inflation mechanisms, which may vary from one coin to another.
EDIT:
Even though on the surface two schemes might seem somewhat similar, they are fundamentally different:
PoW - neutrality, freedom of innovation, hacker mentality, equality of opportunity, game of skills
PoS - entrenched interests, corruptible humans, oppression, inheritance of wealth, game of luck
Pick your flavor of the future.