Ask yourself this:
What percentage of mobile devices in the world CAN access email? What percentage of those devices have a data plan?

What percentage of mobile devices can send and receive MMS? What percentage of them have the service available?

Unless you have a smartphone or a Sidekick, you probably CAN'T receive emails on your device. Most carriers in developed countries allow unlimited or high amounts of messaging, which includes MMS, but meter data sent via email. MMS is limited, but the device and the network usually decides the file limitations, such as filetypes and size. My carrier's MMS system automatically resizes photos when sending, significantly saving data. Even the iPhone downsizes images when emailed from the device! So its like a forced MMS system.

MMS is about accessibility to more users and compatibility with most users as well.

I'm SO glad this review was written. It mirrors my expectations for the N900. I'll get one anyway because of the OS, not the ergonomics, but the phone is something we expect to be reliable and work, and it should've been a focus, not an afterthought. Suggesting the E71 over the N900 because of portrait support and messaging seems a little weak to me, like its an excuse to let the N900 off the hook. I really hope Nokia is taking the consumer demand for portrait support via ASR and better implementation of the phone app seriously and has an answer soon. The N900 has too much potential. We need it to perform up to expectations, even if they're based on imagination. (I mean that too.)