"Store using database" unclear / Request: Dynamic computing

Support:
It is unclear that the checkbox "Store using the database settings below" is not optional - the module doesn't seem to function without it.

Feature Request:
If there is room in this module for on-the-fly computing of the computed field it could be of some use. My example being; I'm using YouTube's API to get dynamic information from videos (# of views for example) and would like that # to reflect the correct #.