Hi,

I believe that connecting such many pins to ground is just "good engineering practice". If you need one power pin, one ground pin and 8 data pins, what do you do with the rest? I usually ground them if it is possible (if they are for example IO pins set for input). You never want to have floating pins for many reasons (in this case mechanical, but may be they'll act as an antenna and will introduce some noise into the circuit if not connected somewhere).

(Correct me if I'm wrong, I'm just an amateur engineer :-))