Usually when there are leaks and rumors focused on upcoming iPhone models, they have to do with the display, certain biometric features, the camera sensors, and things of that sort. That is not the case with the latest leak. Rumor has it Apple will release a dual-DIM iPhone model this year, and a breakdown of iOS 12 reveals suggests it is true.
Apple has not released iOS 12 to the public yet, but it is available to developers and testers in beta form. Interestingly, a component of the beta that is tasked with generating diagnostic reports makes references to "second SIM status" and "second SIM tray status." There are also references in the beta build to a "dual sim device." Those are not-so-subtle hints of what is to come.
The reference to a second SIM tray seemingly points to a future iPhone model sporting two physical SIM slots for dual-slim cards. The alternative is to have a regular SIM tray and an e-SIM for the second one, but that seems unlikely at this point.
Do you need dual SIM slots? It is not a feature that matters to the average user. However, for iPhone owners who travel out of the country, whether for work or play, having dual SIM slots can come in handy. It can also be useful for owners who want to switch between multiple carriers, perhaps one for work and another for personal use.
Based on the timing of past press events, Apple will probably unveil its next iPhone models in September. One of the rumors floating around is that it will introduce three iPhone models, including a larger iPhone X variant with a 6.5-inch OLED display.