It started its life as full fledged pattern matching, but there were just too many things there to cram it in a single release. If you look at proposals and discussions on Roslyn GitHub issue tracker, you'll see the backstory.
So, what we're seeing here is not necessarily the final stage. It's what we get in this release of the language, but more will likely follow.
Yep, I'm aware of the backstory, and the additional planned keywords. I'm reacting mostly to the continued usage of the term for this release without those features, because those being introduced to the term for the first time, won't understand there's supposed to be a difference (and thus not understand the main arguments in favor of pattern matching).
I'm all for C# getting more expressive, but what it calls "Pattern Matching" simply is not the same thing as real honest-to-goodness Pattern Matching.
C# "Pattern Matching" is little more than destructuring, or switch, on steroids.
Much like how the compiler assists you when writing subclasseses so that you've implemented all the required methods, real Pattern Matching (F#) gives you the same guarantees from the compiler that you've handled all the possible cases appropriately.
This makes real F# pattern matching much more useful than "switch with destructuring", and helps you grow your programs in a safe way.
The C# way has all the same problems as the switch statement, which gives no feedback about what cases you've handled.