Too bad I found this post only now — about 6 months ago I bought Synology DS416play for similar reasons myself. Paul shares a lot of great points, and I may reconsider some parts of my workflow. I hope to write about it at some point, but in short I keep Lightroom library and recent shoots on my laptop, while everything else goes to external SSD in USB 3 enclosure. Then all of that is backed up to Backblaze and Synology.
I've also been very happy with Synology as my home digital hub — Apple TV plays movies from it, Sonos plays music, all my photos are available on iOS devices, and all laptops get backed up to it with Time Machine. So far so good, and it feels like I barely scratched the surface of all its possibilities.