Differences between IN and [;database=] in SQL ACCESS

Whats the difference between IN command in SQL and [;database=] to join data from external databases like ACCESS? eg:

select * from table1 in 'c:data.accdb'

and

select * from [;database=c:data.accdb].table1

Using one of those can block the external database on shared disk?

eg: One of users is blocking access to file for others

If not, what could possibly block the file this way?

Answer

The IN syntax seems to apply to all tables in the query, while the 2d syntax seems to be usable on a table by table basis. Also, the IN has the advantage of being a property of the query, making changes to the target BE easy to program.
Eg, with 2 tables, both in external db:

SELECT tblIssues.IssueId, tblStatus.StatusDescription
FROM tblStatus INNER JOIN tblIssues ON tblStatus.StatusID = tblIssues.Status
IN 'H:DocumentsMyFolderMydb_BE.accdb';

I don’t know if the exclusive use of the FE propagates to the BE.
And again: why not just using linked tables ?