Well, I haven’t yet figured out what exactly such component will do, but here are some possible uses:
Avoid the metadata queries at every connection.
Allow overriding of some db properties in the application, like required/not required, provide application default values etc.
Allow defining of formatting, conversions and labels on ‘domain’ level (once for all db columns in different tables containing amounts, account codes, dates, currency codes etc).
Keep lists of possible values (enumerated or from foreign key tables) to be used to populate list boxes etc.
It should be possible to auto-generate most of this at design time.
Hope you get the idea. If anything similar already exists, please let me know.