This is a pretty neat idea to help make content discovery just that bit better. For more generalised Communities like OCD or GEMS, this could be a boon indeed, since people who post there have varying interests, and it helps to reader to find more about what they like. So, those Communities could have a Collection for photography, artwork, travel, personal blogs, etc.

I could also find this useful for myself, given that I blog different types of content every now and then. This way, I could have one Collection for cars, another for watches, and another one for my personal life. Pretty neat idea, mate! I hope his falls into consideration with the HIVE and @Peakd dev team :-)