That is for e-gate registration. Smart Gates on arrival use the same hardware as e-gates, but if you use Smart Gates you are prompted to use the eye scanner, if e-gates, then you use the fingerprint scanner. The non-registered queue for Smart Gates sends you to a validation desk where an officer is waiting.

There are no e-gate registration areas before immigration - at DXB, the most convenient DNRD office at T3 arrivals by Baggage Services, near the taxi queues, as it's generally always staffed. There are other ones in the departure area (e.g. at T3 F/J area just before security, but after immigration, but the last 3 times I went there in the day time there was no one there).

e-gate cards (actual ones you buy from DNRD or the ones included in Skywards cards) are not only available to UAE citizens and residents, they are also available to GCC nationals and citizens of visa-waiver countries. It's not very well advertised though!

http://dnrd.ae/en/Services/Pages/Smartgate.aspx
http://www.dubai.ae/en/Lists/HowToGu...orm.aspx?ID=40

http://www.emirates.com/english/help...-gate-benefits

EDIT: Although EK is of course not the definite source of information regarding immigration rules in Dubai, I am not a UAE national or have a residence visa, but my e-gate works fine

EDIT 2: Finally found e-gate eligibility: http://dnrd.ae/en/Services/ServicesG...7&AudianceId=2 4. Holders of Visa on Arrival