Auto time intelligence is enabled by default, and it applies to each individual PBIX file (there’s not a global option). For most datetime columns that exist in the dataset, a hidden date table is created in the model to support time-oriented DAX calculations. This is great functionality for newer users, or if you have a very simple data model. However, if you typically utilize a standard Date table, then you will want to disable the hidden date tables to reduce the file size. (Tip: You can view the hidden date tables if you connect to the PBIX via DAX Studio.)
There are a lot of good things to think about here.