Module works with Rules, not Feeds

Elsewhere you've said that this module is designed to work with Rules, not Feeds. I am trying to make content available which is currently stored behind a REST server. That sounds to me like I should be creating a Feed of the data -

However, I don't want to fetch ALL the data unless it is required - so that suggests maybe Rules.

Can you give me some idea of the questions I should be asking myself as to whether this is the right module for me, or whether I need to go down a different route?