Have I got some setting that makes this fail? Is it just generally busted? It is certainly no big deal, but it is irritating.
If I'm on my linux box in chrome looking at an app on the google play web interface and click "install" and select my Nexus 5, 100% of the time I get a downloading notification on the Nexus 5 followed in a few seconds by a "error downloading app" popup. If I get on the Nexus 5 itself, search for the app in the play store and click on install it works perfectly.