Any kind of copy protection is useless and it's simply a waste of time "integrating" it into a software because it will get cracked within few days or even hours... It would be nice to install the game and be able to play it without CD/DVD because then the CD/DVD will last longer (it won't be so scratched and eventually unusable) and people (who bought game) wouldn't trouble finding no-cd/dvd cracks.If someone already downloaded game illegaly and likes it, then chances are that he will buy it just because to show some respect to the developers. No copy protection will ever stop this illegal distribution, but quality game and respecting those who buy them - will.
I don't think that this SecuROM ever stoped illegal distributing...