I think it is usually better to install games onto a USB storage drive because USB External SSD is faster than most SD card.
USB Desktop external hard drives also can store more games than most SD Cards, and some newer USB external hard drive are fast enough to run games for the Xbox One and PS4.
SD cards may also be less reliable, and not designed to be running at full speed and higher temperatures for many hours like hard drives, and SSDs which can run without problems for a long time like hard drives, and SSDs which are installed on servers and supercomputers which stay powered ON for many months to years.
USB Desktop external hard drives also can store more games than most SD Cards, and some newer USB external hard drive are fast enough to run games for the Xbox One and PS4.
SD cards may also be less reliable, and not designed to be running at full speed and higher temperatures for many hours like hard drives, and SSDs which can run without problems for a long time like hard drives, and SSDs which are installed on servers and supercomputers which stay powered ON for many months to years.