[ Expect is wonderful. Its role in the past was quite large.]
[Now there are often strictly superior approaches for many problems that would have been solved in the past with Expect.]
So the title can be expanded: Many people who bknow/b they need Expect...do not need Expect.
[On another hand, Expect still has many uses that programmers do not know.]
So, here are examples of more modern ways to do things that once would have been best with Expect:
"Others have given you answers to your immediate problem. I would suggest you look at cfengine as a longer term solution. The problem you described could have been trivially solved by adding a few lines to the cfengine master files at the policy server. On the next scheduled run, all the servers would have downloaded the new config file, seen the new instructions and implemented them." [Rework, explain, ...]
This page doesn't yet explain anything; it only alludes to ideas that those who already understand will recognize. Also, it should be noted that, while Expect isn't the preferred way in 2007 to automate FTP (for example), there are rare circumstances in which an expert might choose to use it.