How many saved files can Assassins Creed 2 have

There are 4 save slots on the PC version as far as I know that can be saved as different profiles, but I don't understand the purpose since the story is quite linear and everything you do in the cut scenes don't seem to make much difference except for the actions that take place during said scenes only and the option to kill or spare the end dude, which also makes no difference. Unless you have a family of people all wanting to play their own profiles or are after a specific line of accomplishments in a specific order... I don't know.