As AJ Henderson and Warrior Bob mentioned, those cables are also MIDI interfaces.
I have several of the cable-style MIDI interfaces, as well as an old eMagic AMT8 and a MOTU 828 MK2. A few of my synths with USB interfaces function as USB-MIDI interfaces, but I rarely use them for that purpose. I also have the Elektron TM-1 interface for my MachineDrum.
For typical MIDI music stuff, the cheap cable-style interfaces are perfectly fine. They generally transmit and receive MIDI notes, and can handle a bit of CC data too. They generally fail when you try to do complex SYSEX tasks, like firmware updates. Even my "EMU" branded X-MIDI failed, so don't think that a nice brand name on a cable-style interface will help. They probably all come out of the same factory in Shenzhen. Just buy the cheapest one you can find.
My MOTU is my go-to interface for firmware updates, I've never had trouble with it. I suspect that the AMT8 would be fine too, but I only plug that in when I need to work with a lot of MIDI devices at the same time, which is rare.
I've only ever used the TM-1 to do a firmware update on my MachineDrum. I thought that since the TM-1 is designed for high-speed sample-over-MIDI transfers, it would make for a quick update. Not at all - the update actually took hours. This is probably wise on Elektron's part - you don't want to add any risk to a firmware update procedure. The process probably runs at a low MIDI bitrate and includes a lot of error correction codes.
For your intended use, the cable-style interface should be just fine. If you decide that you need more ports in the future, look at used 4x4 and 8x8 interfaces. As long as they can connect to your computer and drivers are available, an old interface will be just as good as a new one.