Antonyms for the phrase "being of use" could include being unhelpful, useless, pointless, and ineffective. If someone or something is not useful, they provide little value or benefit to the situation at hand. Uselessness can arise from a lack of skills, knowledge, or effort, or simply not being suited to the task. A person or thing that is pointless is entirely without significance, while an ineffective action or object does not achieve its intended goal. In summary, being of use is a desirable trait, while its antonyms suggest a lack of functionality, efficiency, or relevance.