Anything is better than nothing - it's to protect from fast transients like lightning striking some distance away or ESD.
There's a continuum here. Some energy source / device sensitivity combinations will do no damage with no diode at all, some combinations will leave a smoking hole where your circuit used to be. Faster protection is better, but the difference in protection from fast recovery vs. Schottky is pretty small. I use Schottky and have never seen a failure (touch wood). If the lead to the device is fairly short - say under a couple meters, you will be safer yet. YMMV.