Well there's a good news for Windows 10 mobile users that official Steam app has arrived in Windows Store. Official Steam Windows 10 Mobile app can be now installed on Windows 10 Mobile devices.
This official Steam app provides authentication, trade, and community features to secure and enhance your Steam experience. Using this app you can ensure the security of your account with Steam Guard multifactor authentication, Send and confirm trades with friends, Sell your in-game items in the Steam Community Market straight from your Inventory, Browse the Steam storefront and keep up with the latest games, promotions, and sales, Remotely download and install your games straight to your PC at home.
This official Steam app provides authentication, trade, and community features to secure and enhance your Steam experience. Using this app you can ensure the security of your account with Steam Guard multifactor authentication, Send and confirm trades with friends, Sell your in-game items in the Steam Community Market straight from your Inventory, Browse the Steam storefront and keep up with the latest games, promotions, and sales, Remotely download and install your games straight to your PC at home.