I think it's more of a resource prioritisation thing.
I THINK If the resource is async, it will still scan the document to find all resources before the downloads begin. Adding preload basically just tells the browser that the resource is important and should begin the download immediately.
Hmm, interesting. That makes sense. Thanks for the info.
Every single time I’ve seen it done, it’s been used for all scripts. I’ll have to check at some point whether what you think is correct or not. I can easily imagine it going either way.
(Edit: actually, on reflection, sometimes there may be analytics-type scripts that don’t get this treatment, so yeah, if that’s the case it would make sense.)
I THINK If the resource is async, it will still scan the document to find all resources before the downloads begin. Adding preload basically just tells the browser that the resource is important and should begin the download immediately.
Found this, kind of explains it https://speedcurve.com/blog/preload-scripts/