Shared calendars are a great way to bring other schedules into your Google account and make them visible when you login to that account.
Shared calendars are only visible to you, not to others in your workplace (unless you explicitly share them with others). There is one notable exception: GSuite administrators (typically your IT Administrator) can set up a service account in GSuite, which can allow them to see calendars that have been shared with that GSuite workspace.
Why share your source calendar with your primary calendar?
It makes it easy to manage and RSVP to your personal events from your work calendar without switching tabs or accounts;
You can easily see the actual source event behind the copy that Reclaim creates (so you don't just see "busy" and forget what the source event might actually be).
It's easy to share additional calendars via your Google Calendar settings. Here's a guide on how to share an iCloud calendar with your Google account, here's one for sharing an Outlook calendar with your Google account, and here's one for sharing a Google Calendar with a Google account.
If you opt to share your source calendar with your primary calendar, you may see the appearance of "duplicate events" on your primary calendar. Rest assured that these are not dupes. You can read more about why here.