1.A problem with BTC is that people hoard. Especially those buying it to speculate on price rather than use it for transactions. As more merchants accept BTC this will change. Microsoft and Dell now taking BTC helps a lot. But there is no incentive to hold BTC per se. POS incentivizes hoarding.
Hoarding does have an effect on stabilization as well because of it's finite resource aspect. POS incentivises hoarding trapping the fiat value of the coins into the ecosystem to stabilize the price.
There's one thing I don't agree with... or don't understand yet about XPY... It has been stated in the whitepaper that if there is low demand for XPY, then the POS algorithm will not release as many coins. I get that this helps stabilize price to keep the finite resource limited. But if you hit an extended period of low demand, then the only POS "profit" to come by is through transactions and other services alone. That doesn't bring any new "money" into the ecosystem, just transfer from one to another. But, then again... there's a lot I don't fully grasp about XPY yet.
But then yet, again... there's a lot I don't fully grasp about BTC yet, because it doesn't follow typical norms of real-world economics. I find a lot of the speculation and economics threads here are helpful in some ways, but harmful in other ways.
2.Well this all depends on whether you believe savings create loans or if the direction of causality is loans create deposits. There is still a debate amongst economists as to which is the correct way or if it can be bidirectional. I believe that loans create deposits. And yes, I agree that in time there will be enough financial engineering in place to take cryptocoin loans, trade derivatives and all sorts of fun stuff.
POW is labor, albeit computational. Labor is valuable. POS is idle.
I don't know if I'd call POS an idle. One thing I think we can all agree on is that we have seen what POW coins can do with enough energy and effort behind it... but we haven't seen what a POS model can do with this much effort and energy behind it.
A lot remains to be seen, but until proven otherwise, I'm not going to say GAW can't do it.