Never owned a Walther but have a magnum research bde 9mm that is basically a Walther... It shoots nice, decocker lever is smooth, it's a nice gun. Has a little red button pop up when it's cocked.
I always point my pistol at the floor when clicking the decock lever but I don't guide the hammer down... I've owned it long enough to build some trust with the controls... I wouldn't point it at someone and click the decock button, but then again I wouldn't point it at someone period, sooo...
Having decock lever and a hammer is great for new carrying because it adds a layer of safety. Always makes me feel better.