I needed a way to get optical audio out of my MacBook Pro so I can connect it to a home theatre receiver and this little guy will do it very nicely with the XMOS XU208 chip inside at 24-bit/192KHz. There are cheaper ones on Amazon (~$25) but going by some of the reviews and my own personal experience with cheap USB soundcards, they introduce a fair bit of jitter resulting in music "skipping" every now and then.
Can also use these types of devices to get digital audio out of a smartphone/iPad with USB-C/Rasperry Pi, etc.
Normally the Douk Audio U2 is in the $70-$90 range, so to get it at $55 on eBay, from an Aussie seller (apparently) is a solid deal IMHO.
Unless something's changed in recent years, Don't MacBook pros have a TOSLINK build into the 3.5mm jack?
EDIT: "Apple appears to have removed optical audio output support from the headphone jack on its new 13-inch MacBook Pro with function keys, suggesting it is unlikely to have made the transition in the Touch Bar equipped models either."
shame..
FWIW HDMI can be used for audio as well if your receiver supports it.