In a world where nearly everybody speaks English, and English words penetrate into so many other languages, do you really need everything translated?
Honestly answered, yes, that would be a really good idea!
We prefer reading, watching, or listening to texts in our own mother tongues, because we generally feel much more familiar with them, and we do not have to overcome language barriers.
When your potential target groups see that you took the effort to translate, for instance, your product or your app into their languages and to localize them, they will be grateful and more likely to be interested in buying your product (given that the translation makes sense and reads as if it was written just for them) – and that will guarantee you a higher rate of return.
Therefore, invest into a high quality translation, and be assured that a priceless value will be added to your translated multilingual website, product description, app, etc.