Comparison
Google Safe Browsing and link checking answer different questions
Google Safe Browsing checks URLs against Google's updated sets of unsafe web resources. A broader link checker can add structural and contextual signals such as the visible hostname, redirects, destination changes and the action the page asks you to take.
What Safe Browsing is designed to do
Google documents Safe Browsing as a service that lets client applications check URLs against updated lists of unsafe web resources, including social-engineering and malware-related destinations. Current Safe Browsing documentation includes real-time and list-based modes.
Why a no-match is not a guarantee
A threat-list system is strongest when a destination is already known to the service. New or narrowly targeted malicious pages may exist before they are classified. A result with no known match should therefore not be treated as proof of legitimacy.
What a structural link check adds
A structural scanner can highlight an unexpected final hostname, a shortened destination, multiple redirects, unusual URL encoding or a forced download even when no reputation source has classified the URL. Those are decision signals, not malware verdicts.
Commercial API note
Google states that Safe Browsing APIs are for non-commercial use and directs commercial malicious-URL detection use cases to Web Risk. This comparison describes product concepts; it does not imply that Can I Share This? uses Google Safe Browsing for every scan.