Flash Memory was invented by Toshiba in 1980. Usually Flash Memory is used to store program code that rarely needs to be updated, such as a computer's BIOS or the firmware of set-top boxes or TV. Its endurance may be from as little as 100 erase cycles for an on-chip flash memory, to a more typical 100,000 erase cycles. Flash Memory write and read in blocks (or pages) which are generally much smaller than the entire device.
Like mentioned above, Flash Memory is limited to 100,000 erase cycles, so writing data on Flash Memory is also limited. Once software write something on Flash Memory, it actually acts erase blocks(or pages) and write data even though what we need is just 4-5 bytes. So CE Manufacturers does not want to write any data on Flash based on their policy.
For your information, new generation of memory card formats including RS-MMC, miniSD and microSD has more longer lifetime, but you should make sure it also has lifetime - meaning you have to backup your precious data, because it also has lifetime.