The term "is useful" is commonly used to describe things that are helpful or practical. There are several synonyms for this phrase that can be used in certain situations. "Valuable" is a good option when describing something that is worth a lot or is important in some way. "Beneficial" and "advantageous" are ideal for highlighting the positive effects of whatever is being described. "Convenient" works well when discussing something that is easy to use or saves time. "Effective" and "helpful" both accurately convey the idea of something being useful. For more specific situations, words like "practical," "functional," and "utilitarian" may also be good choices.