I think expect is a result of having no programatic interface for command line tools. I ofter wonder how much more useful these command line tools, and how many hundreds of man years would have been saved with buggy text parsers, if there was a programatic stdin/stdout, in addition to the one for humans, from the beginning.

But, with the reality we live in, expect helped me many times in the past. These days, I use python's pexpect for the same use cases.