See the SAR Ireland crash for proof that a navigation database is only as good as the information put into it.
In fairness (to Honeywell at least) an EGPWS database is not intended for navigation, and certainly not meant to have the granularity required to have a 200 ft 'rock in the ocean' in it. The database is primarily aimed at the FW world, and the market size of the RW world renders the cost of providing this level of fine detail, globally, prohibitive