Useful for quick searching
The app is structured slightly differently than the website, specifically in available filters, so it isnt good for selecting a particular part, but it is good for quickly looking for a kind of part, something the website isnt particularly good at. Datasheets load quickly so it is a nice reference when assembling or testing a prototype on a bench where your computer may be out of reach.
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Digi-Key Electronics, v2.9.0