Creating and maintaining your help center needs a substantial amount of work even before starting to think about the content. Many large businesses with sophisticated requirements decide to assemble their own solution. However, for most small companies and startups it's not uncommon to struggle to find time and resources and working on a help center portal as a separate project.
This is where a hosted solution comes into place. By going with a hosted solution you are left free to focus all your efforts on building your amazing product and actually educating and helping your customers instead of reinventing the wheel and building a help center from scratch.