https://unix.stackexchange.com/questions/65803/why-is-printf-better-than-echo

Q: echo
echo didn't accept any option and didn't expand anything. 
All it was doing was outputting its arguments separated by a space character and terminated by a newline character.

Q: printf
printf, on the other hand is more reliable, at least when it's limited to the basic usage of echo.
printf '%s\n' "$var"