Taken from Emirates Airways website, there’s a page that has this section:

Dubai immigration procedures
As an added security measure, Immigration Authorities at Dubai International Airport are now conducting random eye screening for visitors to Dubai.
Visitors asked to proceed for eye screening are required to present a hard copy of their visa or a printed version of the visa number confirmation page at the screening counter. If you do not have a copy with you, a charge of AED 30 per copy applies ‑ payable only in AED.

Other parts of the site talk about how travelers can obtain their visa electronically, and how they are forced to install a “smart app” on their “smart phones” otherwise they are denied entry to the country. But when it comes to this random screening of the visa they need to have a hard copy, otherwise they must pay a fee. “OK, fine” one might say, but then that last sentence is what completes the ugliness of this affair: “payable only in AED.”, and this is for a foreign traveler in the passport control area. I.e. they haven’t yet legally entered the country and they’re required to pay in a currency that they’re not supposedly carrying yet.

As a software developer this smells like a bug in the system that requires fixing, but the system is already so complex and possibly many other bugs of higher criticality exist. I don’t think the authorities are intentionally trying to make life harder for tourists, this is why it feels more like a bug in the system.