If anyone is wondering why they have an explanation date or why they changed from the point system to currency, here's a little writeup on it:

There seems to be a lot of misinformation and assumptions going on with this transition, so I thought I would do my best to explain why Microsoft is doing this for people who just think they may be getting cheated out of points.

No, it's not just exchanging one system for an almost identical one. Right now, Microsoft is still in transition to a unified ecosystem. They took what Apple created with the Mac ecosystem where all of their devices (iPhone, iPad, Mac, Macbook, iPod, iTunes, iCloud, etc) communicate flawlessly with one another, and they're trying to improve upon it.

What this means is that they want you to be able to have a single login between all of the Microsoft devices. One profile, one account, and very importantly, one online wallet.

As it stands right now, Microsoft points cannot be used to buy Windows 8 applications, WP8 apps, etc. This is a fracturing effect that they really don't want. On top of this, there have been numerous cases of exchange rates not melding well with the points system in certain countries. The value of a game and the value of 400 points might be different values. It could be a headache to create a balance for what 400 points go for in different regions.

This is also why people are saying that the currency thing is causing prices to go up. They aren't going up because Microsoft can do that and they want to screw over people... they're doing it because they have been doing this balancing act of the cost of games in local currency, the cost of games in points, and the cost of points in local currency.

Now as far as the expiration of your points/currency goes, they will expire, this is because they are not exactly just turning your points into local currency. They are submitting a promotional deposit into your account. Due to financial reasons, they can't really just give people money without it looking terrible on the business/financial side leading to bad reports to investors and whatnot, which is never good for the company or its customers. What they can do, however, is write that money off as a promotional investment in order to give everyone what they're owed, but this means that the money must fall under the promotional guidelines... That's why there's an expiration.

So what would be better for Microsoft... should they adapt their other online stores (Win8, WP8, etc) to this headache of a system in order to keep an arbitrary point system, or should they go ahead and transition away from this system that, while good in theory, was causing all sorts of problems for them in terms of unifying their stores?

There is going to be a bit of transition pain for some people, but once it goes through it will be a better overall system for both Microsoft and us.