Update README.md and note

Author: aoxolotl

README.md

@@ -15,9 +15,9 @@
 
 ## Installation
 
-*Note*: Newer versions (>=0.4.8.2) of DataTorch client require `libmagic` for file uploads
-to datasets. Your system may or may not have `libmagic` pre-installed. Please
-make sure you have `libmagic` installed before proceeding.
+*Note*: Newer versions (>=0.4.8.2) of DataTorch client use `libmagic` for more 
+accurate mimetype guessing. This falls back to guessing via extension. Consider
+installing `libmagic` if you have issues with file types uploaded to DataTorch.
 
 ```bash
 pip install datatorch