As stated by others, external sound "cards" (boxes would be a better term) are still prevalent in pro-audio applications, and may have evolved from internal car

As stated by others, external sound "cards" (boxes would be a better term) are still prevalent in pro-audio applications, and may have evolved from internal cards not only for the convenience of plug-and-play, but to allow accessing cables more easily than diving behind a PC tower. There are still "cards" being made for pro-audio users, that embed DSPs for computing plugin algorithms [1]. Not quite the same application, but an interesting parallel. [1] https://www.avid.com/products/pro-tools-hdx https://www.avid.com/products/pro-tools-hdx