But if you don't do this, you can still use <tab> - and if there are more than one option it'll list the possibilities. With this you just have to tab through all the options to see what is there.
If you have 3 options starting with the same prefix, it's fine, but if there's hundreds (e.g. a directory with a lot of libraries starting with lib<something>), it becomes highly annoying and it's better to just give the list so I can type the next letter
(Say you have a directory with two subdirectories "fooabc" and "foo123". You are in the directory and you type "cd f" and then hit tab. This will complete to "cd foo", and if you hit tab again, then it will show the two options, and then you have to enter "a" or "1" to disambiguate.)