Depending on the country, SD cards may be used to share media, like photos, music, videos, etc., and to also copy media from others and play them on one's phone

Depending on the country, SD cards may be used to share media, like photos, music, videos, etc., and to also copy media from others and play them on one's phone. Yes, it's very slow, but many people who use them don't know and don't care as much about the speed. SD cards are also not very reliable, but again, many people who use them don't consider that to be critically important.