Gems are for crafting Trading Card Packs for games. Some games you can craft trading packs for as low as 300 or 400 and some as high as 1,000 gems.
There is an easy way to obtain the badges, https://www.steamcardexchange.net/index.php?gamepage-appid-
You use that link and add the App ID of the game after the - and you can get the Trading Cards, Badges, Emoticons, Profile Backgrounds, Card Artwork and Foil Trading Cards. Including the new Points Shop items.
I've already done that with Resident Evil 0, it is highly recommended article and image names are changed as to fit wiki standards.