MGM filed both these applications on an intent-to-use basis, meaning the company is not yet using these marks in commerce but has a bona fide intention to do so in the near future.
According to MGM's website, it appears the company is already operating "MGM Village" and "MGM Festival Grounds." Thus, it looks like the company is seeking to change the name of these venues.
In some instances, a new trademark may be "tacked" onto an old trademark, giving the new trademark priority that relates back to the first use of the old trademark (for example, MGM could have obtained priority in LAS VEGAS VILLAGE relating back to the first use of MGM VILLAGE). However, tacking only works when the new trademark is the legal equivalent of the old one (i.e. exactly the same or almost exactly the same) and the underlying goods or services are the same or substantially the same.
In MGM's case, "Las Vegas" is not the legal equivalent of "MGM" and thus tacking cannot be used (even though the underlying services are exactly the same).
For trademark owners, this demonstrates an important consideration - choose your trademark carefully. If you decide to change your name down the road, chances are you will need to file another trademark application if you wish to give yourself nationwide rights in the new name.