It definitely reduces cheating, but mostly just by raising the bar of entry (not by that much as evident in day 1 cheats being present). I doubt it's effectiveness though, since most games you can do some quick research and find $5 cheats that will go undetected (hell even free cheats can work if you do a little more research on doing the injection part manually yourself).

You can also never stop cheating, but the anti-cheat they install on your computer is just an extra attack vector for hackers, etc at this point, since it obviously doesnt work as intended.