It can be both. Good art tends to allow a measure of interpretation outside of what the artists originally intended.
Dunno how in tune you are with random factoids but Lucas is on the record saying that his favorite episode in "The Clone Wars" is "A Sunny Day in the Void", where a bunch of droids are stuck in the desert. So...yeah, there's definitely _something_ he gets out of this series that might not line up with the fanbase at large.
He also wanted to double down on the midichlorians and the Whills for the sequels, so it definitely wasn't a one-off for him.
As for me, I don't hate the idea that a spiritual quality can have a physical component to it. (Makes you think about if a parting of the Red Sea or an ax head floating are "truly supernatural" events or more "natural, with mechanisms we can't understand".) I suppose it's a bit coarse that it's used to boil mysticism down to a number for comparison, and it certainly wasn't _necessary_ to move the plot along, though.