Why are written sources most valuable to historians?

In fact, the written sources are not reliable documents. People wrote them. Very often such sources were inaccurate. People are not always objective. Quite often, various opuses were written for money and taking into account the interests of the person who paid. Many written sources were rewritten by people from different languages ​​with the loss of content. Written sources may have historical value due to the fact that they have simply survived to this day. Historical truth quite often has nothing to do with what is written. But according to written sources, you can make comparisons with other artifacts and track the mood in society, various events. The written sources are fairly recent when compared to other artifacts.