It's bad practice. My kids are growing up expecting everything to auto save. When I let them play an older game they always turn it off without saving...
It annoys me greatly too that saves are specific to the user who starts the game. My impatient kids never check who is starting the game, then they can't find the right save game. I had a bunch of Minecraft worlds under 4 different users, frigging mess.
At least I haven't had the displeasure of a game that only saves at checkpoints in a while. I hate it when a game holds your system hostage until you get to the checkpoint, or lose all progress from the last checkpoint.
Anyway screw single save slot / auto saves. Sometimes I just want to save and blow off some steam, burn it all down, go on a killing spree. Then go back to where I saved next time. Game, why you so serious.