When sharing the dashboard,I feel link and snapshot both can achieve the same effect.
From the documentation:
A dashboard snapshot is an instant way to share an interactive dashboard publicly. When created, we strip sensitive data like queries (metric, template and annotation) and panel links, leaving only the visible metric data and series names embedded into your dashboard. Dashboard snapshots can be accessed by anyone who has the link and can reach the URL.
Sharing the link to someone means that they’ll need access to your Grafana instance and possible also permission to access your dashboard.