What are some alternatives?
When comparing Deckboard and Elgato Stream Deck Mobile, you can also consider the following products
Macro Deck - Use smartphone as macropad for pc
Monect - Make the best use of sensors on smart device to control PC, simulate steering wheel, game-pad...
Bitfocus Companion - Bitfocus Companion enables the reasonably priced Elgato Streamdeck to be a professional shotbox surface for an increasing amount of different presentation switchers, video playback software and broadcast equipment.
MATRIC - Control PC applications via smarthone/tablet. Especially suitable for space/flightsims.
Unified Remote - Unified Remote is a software app available for iPhone, Android, and Windows Phone mobile operating systems. It's designed to turn your smartphone into a universal remote. Read more about Unified Remote.
LEA Extended Input - iOS/Android app with windows server to control functions in games via your smartphone/tablet.