Why does the Chinese HTC One have a removable back cover and microSD card slot?

When Samsung launches a new phone, it looks the same, regardless of the country you happen to be buying it from. The same thing can be said about the iPhone. The software might be tweaked a little for local tastes, but cosmetically speaking a European Galaxy or iPhone looks exactly the same as it does in Thailand or Malaysia.

So why then does the Chinese version of the HTC One have a removable back cover, microSD card slot, and two SIM card slots? It means HTC needs to have a separate production line for this tweaked model. And here’s another question: If the back of the Chinese One comes off, then why can’t the battery be swapped? Samsung can do it with the GS4, so … what’s the excuse here?

I’m honestly trying really hard to understand HTC’s strategy, but I just can’t.