Demon's Souls is one of the more tedious games of the genre. Healing items being consumable means that if you struggle with the game, you'll oftem have to go grinding for items.
The World Tendency stuff was so opaque that I had to go look up how it worked and how it affected the game, and once I understood it, I didn't want to have to deal with it. Fortunately it doesn't matter much for most players and can safely be ignored unless you already know what you're trying to do.