From the post on rebble.io

> We made it absolutely clear to Eric that scraping for commercial purposes was not an authorized use of the Rebble Web Services.

So, another point of consideration is whether looking at names and pictures so you can personally favorite them constitutes as commercial use. Based on what Eric said, I don't really think so.

> I wanted to highlight some of my favourite watchfaces on the Pebble Appstore.

It was for a commercial purpose. Not a personal one.