I'd say the common ones (besides educational) are

- private, on-device models (possibly with lower latency than models via web API); also edge devices

- algorithm research (faster and cheaper to prototype new ideas)

- cheap tasks, like classification/categorization; sure, you don't need a decoder-style LLM for that, but it has the advantage of being more free-form, which is useful in many scenarios; or maybe a sanity checker for grammar; or even a router to other model (GPT-5 style)