Most teams handle this in one of three ways, and each has a real cost. Copying data out of Salesforce into Word or Excel is slow and error-prone, since every manual step is a chance to copy the wrong figure or use an outdated version of a record. Routing documents through a third-party generation service moves customer data outside the org, which raises questions for any team handling regulated or sensitive information. Building a custom solution in-house is a real engineering project, not a weekend script, and it needs upkeep every time the underlying Salesforce org changes.
NativeDocs is built to remove the tradeoff rather than pick a side of it: document generation that runs on Salesforce, with template changes an admin can make without asking engineering for a deployment.