Hi,
Because the plugin runs on your local server, and there is no monthly fee for 3rd party hosting, only the generic google keyword suggestion service can be used. Unfortunately since that is a free service, it cannot be restricted to the given website, all you can do is turn it off, if it is not needed.
Typo detection is a very resource heavy operation, when executed on the server side. As an alternative, you can use either of these features:
– Additional keywords metabox
– ..or synonyms feature -> this is more global