What are ambiguous password characters?
Characters such as 0 and O, or 1, l, and I, can look alike in small text, handwriting, printed labels, and some fonts.
When exclusions are useful
Removing look-alike characters can reduce transcription errors for router labels, temporary access credentials, support calls, and other workflows that require manual entry.
Compensate with length
Every exclusion makes the available alphabet smaller. Increase the password length when possible, preserve random selection, and use each generated value for only one account.