When you share another calendar to a different account, it only shows up for you, not others who view your calendar, unless you explicitly share that calendar with those colleagues. Even then, if those coworkers use Google's "Find a Time" feature, they will still only see events from one calendar -- your primary one.
Reclaim creates synced copies of events from other calendars and pushes them to your primary calendar (or any other calendar you choose), making them visible to others -- even when they use Find a Time. Sensitive titles and descriptions are stripped away from these blocks, preserving your privacy. It keeps those synced events up to date when things change on the synced calendar, which means you never have to worry about updating events yourself.