I've setup a second monitor on my desk. I rarely use it, because I'm away so much, so it just shows art or whatever I'm into at the moment.
I also threw a folder onto Google photos and then linked that up with a Chromecast on one of the office TVs. Perfect for art. I think the original tool could work great in both cases.
This is a cool app, but isn't the idea to integrate it somewhere you end up looking already, rather than have to think to look at it and click the shortcut? I have the same problem, I always cmd+tab between windows so I never see my desktop.
In the past I used a chrome extension called tab.pics that shows a new landscape image pulled from reddit on every blank tab. It was kinda buggy though, it rarely shows the caption of what I'm looking at, and the source material isn't always that interesting or high enough resolution and sometimes doesn't load at all.
Just an idea, but if you converted BackgroundifierBuddy to a chrome extension I would totally use it.