Among the customers, your analysts' team and employees visit your web page too.
For example, the analysts check the correct work of the advertising channels and SEO tools. The employees might check the excellent work of the script (developers, QA) or check some information about the service.
In this case, the general statistics will include these sessions with inserted numbers data, and some inserted numbers from the pool will be attached to these sessions. That means:
Your conclusions about the statistics won't be accurate.
The numbers from the insertion can be attached to the non-target session.
To avoid this situation, use blocking insertion by IP for your employees and analysts' team.
To enable this function go to the "Call tracking" => "Block by IP". Add the required IP address (IP address of your company) and save it.
Pro tip: you can also use a filter for your business IP in Google Analytics.