People would buy the 12gb model for the lower entry cost. There are only a handful of games that have install sizes larger than 12gb (Resident Evil 5 is one) and users can always delete old game content to make way for others. Not very convenient but doable.
The other reason would be to purchase whatever HDD or SSD you want for the system. I don't know what you can get for 70 Euros but you can shop around and you could end up sitting pretty.
What I don't understand is why the 12gb isn't launching everywhere. In the US it would have hit that $199 price. In japan probably 20,000 or 21,000 Yen. Maybe EU/PAL is serving as a testing grounds to determine how the market will react and they will respond accordingly.
Sony is primed for a strategic price drop next year and I expect decent sales for the system until 2014. A great finish toward the launch of the PS4.
Before the PS3 everyone was nice to me :(
