Thanks for the great question. Couple points:

1. I thought both statements were exactly the same. I sat there looking at it for about 4 minutes before I noticed the difference between the two. I must be going blind.

2. Technically, both statements could execute if you just happened to have a stored procedure with the name [use master dbcc showfilestats]. I know, this is crazy but did want to be the first to mention it 🙂