Entity lists versus CSV files

Hi all,

I am trying to link 2 entity lists to 1 form. One of the entity lists would be used as input filter for the form (as a csv file), so not to write/update to an entity list. My first question is: Is it possible to use 2 entity lists for one form (if only 1 entity list is being used for updates and the other just for filtering)? If this is possible this also generates my second question: Why using CSV files instead of entity lists if one can update entity lists through the API (easier for workflow automation) and csv files need to be updated manually?