I don't subscribe to Ancestry.com
so I don't know anything about searching
it. or how long it takes them to make a new database fully searchable.
It may be that the database
1) is a work in progress and should be searched about once a week to
see if your surnames have been added;
2) Has only a limited number of names in each database.and they are
already all up on the Internet.
If you subscribe to Ancestry, you should ask their help people
what the "catch" might be.
I think that since they just announced this dataqbase, it may be
best to wait for a little while before attempting to use it.