Bugs don’t care about what kind of computer you’re playing on, but actually, when Sims 4 was released, I couldn’t play it, while my Sims 3 game ran just fine on highest settings. My computer would shut down after about 4 minutes. Which probably was caused by the fact Sims 4 demands more of your video card than Sims 3 does?
Sims 3 has never caused performance issues for me, without having any technical knowledge whatsoever ;) I did always make sure to have a good PC, that’s true, the game indeed needs that (and the last computer I bought because I wanted to be able to play Sims 4, though it is an additional blessing Sims 3 loads so fast now in comparison to before) and it’s worth it for me. I seriously don’t care if it’s a casual game or not, I’m not casual about it ;)
I actually know several players who returned to Sims 3 (and 2, or play all versions) and even two who started playing Sims 3 after being disappointed with Sims 4 (one was a disappointed Sims 2 fan who learned to appreciate the game after all, the other is someone who had never played Sims 3 and started with Sims 4). So, what does that tell us? Nobody is the same and we all decide for ourselves what a game is worth for us.