I put DLC is not necessary for my game, because it usually depends on what platform I am playing on. I answered the question from the Sims 4 perspective, and that some DLC for Sims 2 is no longer supported. I own pretty much everything for Sims 4 on my console, which doesn't allow DLC, so with my packs, I have to work around that. If I wanted to create an Elsa, I have to use what is available to me with what I own. Most sites also don't support DLC for the Sims 2, and so once again I am using what I have. So, in that perspective, DLC is not necessary for me to play the game.
However, for Sims 3, which supports DLC, and owning the base Sims 4 game on my PC, I have quite a bit of DLC. I usually download DLC if I want more hairsyles, or a specific character in my game.