I soldered a grove cable to the 38&39 connectors inside mine and it sticks out the end above the card slotr.
I wager many people use the card reader for logging and with an atom you only get the rear 1&2 pins which limit you to i2c if you want lots of sensors and not all the m5stack sensors are ei2c
they could make a i2c card reader too, then it coul be part of i2c chain,. although i2c is slow than spi and not work with standard sd library, so would have to be a custom chip controlling it and probably just for pushing data tto log plus extra functions for
â˘format card
â˘does file exist
â˘does folder exists
â˘make file
â˘make folder
â˘append to file
â˘move file to folder
â˘delete file or folder
â˘push current date and time to chip so all create-modified time accurate but not integrated rtc