Squeak, for what its worth I agree with you. It is still de rigeur for midi transmission to use MIDI din jacks. And as far as I know it is still the ONLY way of direct keyboard to keyboard communication (without a PC in between controlling at least one of them).
Sadly, or rather expectedly, I reckon Yamaha are doing it a) because its a low end keyboard and as such the users are also likely to be "low end" and they can save a few dollars on construction costs and/or
b) deliberately leaving them off to force the purchase of the "next" model which does have them.
I cannot put MIDI jacks and floppies on the same page as they are two different things in my view. Floppies have been for all intents replaced as a technology many times over. They are ridiculously slow, unreliable and a very dated method of data transfer. Despite protests to the contrary!!
Whereas MIDI jacks are a vital ongoing harware connection, much the same as an audio jack. And until some company installs a host and device socket + the software for two keyboards to talk directly with each other, then MIDI sockets are going to be around for a long while yet. The omission on the keyboard you mention Squeak is, in my view, entirely commercial.
[This message has been edited by miden (edited 08-05-2008).]