This is another, rather bizarre example of WordPress promoting monoculture. Even funnier is this misguided quote from the email:
If you don't already have the WordPress mobile app for your smartphone, you'll want to download it so that you can upload pictures and post to the site right from the party. It would be a good idea to add the site to your mobile app before your party so you don't have to worry about it later.
Paraphrased: “So that you can participate TO THE MAX, post to our hosted silo and download yet another app that you’ll delete straight away”.
Nevertheless, I plan to download the app and try it out as I’ve never used it before and WordPress UX tends to be pretty good. Perhaps then discuss the whole thing in #indiewebcamp on freenode to brainstorm a better way of doing this topic-based aggregation.