The Executable code MUST be in RAM.
The graphical background on which you shall be able to zoom in/ out MUST be in RAM, what difference does it make to load it from the DVD or the Hard Disk except wasted media and redundancy?
Money.
If a game is published exclusively on DVD, then I'll have to buy a DVD drive - and I can be *very* conservative on things. My burner, for example, is only one year old.
I'd prefer games on CD-ROM, because a CD-ROM drive is what nowadays everybody has.
Publishing a game on DVD ONLY is good for hardware manufacturers, but not for the one who has to spend the money.
