So could SaaS LLM or cloud/api LLMs not offer this as an option? A guarantee that the "same prompt" will always produce the same result.

Also the way I usually interpret this "non-deterministic" a bit "broader".

Say i have have slightly different prompts "what's 2+2?" vs. "can you please tell me what's 2 plus 2" or even "2+2=?" or "2+2" for most applications it would be useful if they all produce the same result