Last year Valve released Steam Chat for the desktop, and now its messaging service is fully mobile with a dedicated app for Android and iOS. Naturally, it cribs the desktop version's features, including:
Friends List - See who's in game or online at a glance. Never miss an opportunity to play.
Rich Chat - Your chats get even better with higher fidelity links, videos, tweets, GIFs, Giphy, Steam emoticons, and more.
Invite Links - Add new friends on Steam with a link. Generate an invite link you can text or email.
Customizable Notifications - Mobile notifications mean you'll never miss a message or game invite. You can customize your notifications per friend, group chat, and chat channel.
Group Chats - Get everyone on the same page. Groups make it easier to do things like stay in touch with your communities and organize game night with your best friends.
You'll have to try it out to see if that's enough to pull people away from other options like Discord, but at least now there's proper competition and voice chat should be the next feature added. According to Valve, now that Steam Chat has its own app, and Steam Link is available on both mobile platforms, the main Steam Mobile app will see upgrades that focus on security. Expect to see a better Steam Guard soon, with one-touch login, QR codes and the like.
Source: Steam, iTunes, Android