Con One of the most dangerous languages around
What it is mostly used for are file system operations. Guess what it is bad at? Operating on files. It automatically splits and carries out filename expansion on every single string resulting from variable expansion and command substitution unless quoted, by default on whitespace, whilst spaces are very common in filenames.
Before that, it even does pathname expansion, so woe to anywone who does not want to actually operate on files, but has a globbing metacharacter stored anywhere in a variable.
This means what you store in a variable is not going to be what will ACTUALLY be accessed.
If an empty variable is unquoted, it disappears completely due to word splitting, sometimes leading to applications signalling a missing parameter at a wrong position.
If quoted however, said variables cannot be iterated over in a loop, no matter what character one uses for word splitting.
If you use any globbing pattern with a command, be sure to use -- after the option arguments or if none are present, before starting the pattern with a mandatory ./
Otherwise, another Bash script run gone wrong or a hacker can create files named like an option ("-f", for instance) and your program will happily accept it as such, if it results from globbing.
For interactive use, it is convenient. For programming, it is a no-go.