This is why messaging is a threat to Google and Facebook -- it's an entire ecosystem that sidesteps their channel.
An example like WeChat is funny and interesting because payment functionality is something you'd think should be either a dedicated app (like what PayPal, Square, and others are trying to do), or a core function integrated into the OS itself (like what Apple is trying to do, especially with their new fingerprint thing making their phone more secure).
WeChat being able to get into the payment space is interesting precisely because (a) they are not a dedicated payment company, they've only just figured out how to monetize their user base in a unique and innovative way, (b) they're not a phone manufacturer, and (c) they're not a mobile OS company.
I would not have predicted this at all a few years back. So I think a few years back, I would have agreed with you simply because I would have not thought of it, not because I actually didn't care for it.
edit: coin Henry Ford quote here about faster horses
OTOH, US sites and apps have been moving in the opposite direction. Facebook itself acknowledged this by moving to an "unbundled" app development strategy.
Facebook is currently rather incapable of delivering what I originally signed up for when I joined: keeping posted about how my friends are doing, and thus having the incentive to post something about my life as well because my friends could see how I'm doing. I can't in practice control what I see and how much I see from each friend. Things happen and I don't know about them until I happen to read through my friend's timeline manually. I don't know who actually sees my posts. That makes it rather useless.
The core of what Facebook used to be would be really simple to implement and most people wouldn't genuinely need much more.
Now, I don't know how much such migrations will affect user-base (and I don't guess too much) but it can be noted that this is also the user-base that does online shopping, rates products and does a lot of things online, so this is certainly going to put a dent.
Payment processing is a total commodity business that is super-resistant to increasing its tiny margins, which is what would need to happen to monetize it to the tune of a 10 digit valuation.
In comparison layering advertising or premium features on top of messaging is a much more feasible way to generate revenue, since that is pure margin. It's not a superficially sexy / hand-wavey though.
If you're in a chat app all damn day (like all my family is), and something comes up (OMG it is Dad's birthday), I'd rather just get the shopping, reservations, etc done right then and there at the point of relevancy.
WeChat's success isn't about having the credit card, it's about making that moment of action extremely fluid.
WhatsApp CEO responding to a similar question in an interview.
"The basic idea will continue to be a simple messaging app."
"That's the beauty of an open and free market system, you can go download another application that let's you do that [share ephemeral photos]"
Messaging should be private; not a platform.
