According to Apple rumormonger Luke Miani, Apple’s replacement for the MacBook Pro will include a high-speed SD card reader. We’ve already seen plenty of rumors that the SD card reader was making a comeback, including leaked schematics from Apple. It makes sense that Apple would put the fastest reader in its pro machines, but what are the advantages for users? “While it’s also possible to carry around an SD card reader that connects to USB or lightning ports, built-in readers are one less thing to carry around, they work more reliably, and they’re much, much faster than dongles,” Devon Fata, CEO of design company Pixoul, told Lifewire via email.

Speed

SD cards are rated by their data transfer speeds, both for reading and writing data. UHS-II can transfer data at up to 312MB/sec, three times faster than UHS I’s maximum 104MB/sec. This matters in two places. One, when saving the images from the camera, and two, when transferring them to a computer for storage, viewing, or editing. When recording the images to the card, this added speed can be crucial. These cards need to be able to record 4K (or bigger) video at up to 60fps, without any glitches or slowdowns. “UHS-II is capable of a much faster transfer speed to the computer when using a compatible UHS-II card that professional content creators would likely use for their projects,” photographer Rassi Borneo told Lifewire via email Most people, including pro photographers, can be happy with UHS-I speeds. It doesn’t matter that much if your photos take a little longer to transfer, because you’re probably making a coffee anyway. But if you shoot many gigabytes of video, or you end up with thousands of raw images after a photoshoot, then speed is more essential. “High-resolution photos and video are some of the largest files around. In many cases, it can be faster to physically mail SD cards or other physical storage media with these files instead of sending them over the internet,” said Fata. And cards aren’t just for photos and video. Many audio devices record to SD cards, although audio doesn’t need anywhere near the bandwidth of video. And you can also just use an SD card for plain old storage. For instance, you could slot a large-capacity USB card into your MacBook and use it for Time Machine backups. The added speed of UHS-II makes this a lot more practical, if also more expensive.

Dongles

Right now, you can achieve these speeds with external USB-C card readers, but having a slot built in is more convenient, and more reliable—not least because you can’t leave the dongle at home. “In some instances, a dongle will not provide the full transfer speed that UHS-II SD cards are capable of providing due to the quality of the reader, or the quality of the USB cable used to make the connection,” says Borneo. Yes, at these speeds, the quality of your USB cable can make a difference.

Downsides

At these prices, SD cards are in external SSD territory, and even more expensive. But you can always use old, cheap, slower SD cards in the same slot, and use those for general storage or backup. You must also consider compatibility. It’s no use buying a fast card if your camera can’t use it. It’s just wasted money. And SD card prices tend to fall over time, so buying a faster card to “future-proof” yourself is also a waste of money. The same card will likely be much cheaper when you can actually make use of it. As a rule of thumb, only cameras focused on high-end video capture will have UHS-II compatibility. UHS-II is the future of fast storage, and building it in means your Mac will be capable, should you need it. But far more exciting is the SD card reader itself. Just having one built-in, regardless of speed ratings, is a boon. We can’t wait.