marshmallow and sd card made internal

[AC Question]

I have the Samsung Galaxy Tab A which just updated to Marshmallow 6.0.1. I have read that under marshmallow android can now use the sd card as internal storage, but when I go to storage my sd card is listed but there is no way to tell the tab to use as internal storage. My 2 questions are:
1) is it wise to use sd card as internal
2) How do I do this if it is wise