If you are operating at a scale small enough where a single person is responsible for applying Terraform, and there are never two or more users interleaving applies which could collide, then you don't need TF cloud.

If on the other hand, you have multiple devs, committing changes, and applying them, then you need something like TF to ensure that the applies are consistent, ordered, and auditable.

For personal use? You don't need TF cloud, but the problems it solves get obvious as you scale up.