So I think I know the main use case for F# 3.0's Type Providers, i. e. better Intellisense when working with data stores that use them. Are there other use cases for Type Providers or is that pretty much it?
I think you'll find that there is really only 1 use case for F# Type Providers - that is, getting strongly typed data from data sources.
What I think you might be asking is what good is getting that kind of type information? Well, as you mentioned, it allows you to use intellisense better, but I think that's actually a side effect or more of a happy coincidence.
I think you'll find that the benefits of having strongly typed data available are inline with the benefits of having a strongly typed language to begin with.
Interestingly, if you take a look at the page that has (what I believe to be) the original spec/proposal/design document for type providers, you'll find:
(emphasis and edits mine)