rtcvb32: Automatic saving has it's place... However it's not always wanted. Actually automatic saving could be a death sentence in some games.
BioForge for example, if you do something out of order you literally can't complete the game. And of course if you only save in 1 and never experiment, then when you make a big mistake you just have to start the whole game over.
As for having to quick save often, sometimes i wonder if some games are just too hard, where quick saving and constantly quick loading and repeating until you get through a sequence that would take 2 minutes of game time but two hours of actual time. I remember one such sequence in
Fade To Black where you had to go across a catwalk with like lasers or turrets on either side shooting seemingly at random at the spots right in front of you...
Which is why the optimal balance is (IMHO) to have autosaving at the start of each level, and have a manual save system too. I can see checkpoints working, as long as they're paced well. Trouble is, they usually aren't, at least not in my experience.
With respect to difficulty, it's hard to say, and I think it depends on the game and what you're expected to do. Sunless Sea is a good example of this for me: because of its heavy reliance on -- apparently -- RNG to determine specific outcomes, I'm not ashamed to say that I save-scummed through several of the encounters in the game. Oh, and there was MoH:AA and it's infamous "Snipertown" level.