I'm neither assuming that a game is perfect or that the designer's vision is always correct, but the designer is intending for you to experience a game a certain way, and it's often most fun that way. If certain strategies are dominant such that they invalidate large portions of the game that are there, it usually results in that game being boring. Your mileage may vary, of course, but that's how these things tend to go. The Witcher is a much more interesting game for me when you utilize potions, oils, and monster manuals, and I found the combat to be quite boring when I didn't know how to interact with those systems and instead just reloaded saves for better dice rolls. By forcing you to play a certain way, like by omitting certain save systems, they're making sure you play the way they intended, and if the game is as good as they hoped to have made it, it will result in the most people having the best time.
Here's another example. Batman: Arkham combat is an amazing replication of what Batman is in video game form. It's one man taking on dozens of others, usually more lethally armed than he is, with some athleticism and a bunch of gadgets. You're incentivized via the scoring/XP system to never button mash, use every move in your arsenal at least once, never get hit, and to take out every enemy in the room in a single flowing combo. However, it didn't steer most players into playing that way very effectively (at least on normal difficulty), and many leave the combat system disappointed that they can beat it just by attacking with X and countering with Y.