I've covered a numberfew of practical uses for attaching a license like the WTFPL in a response to a similar but more pointed question. YourThe claim that CC0 is more liberal is incorrect as CC0 comes with a number of limitations the WTFPL doesn't have such as limitations on:
- Patent use;
- Warranty;
- Trademark use; and,
- Liability.
In fact WTFPL has no restrictions whatsoever other than to change the license name if the license is changed. WTFPLIt's is also useful if you plan to dual-license software and don't want to fall into the permissive license attribution landmine, or copyleft just yet. And since there's no “Public Domain” dedication WTFPL may can make sense in jurisdictions where some law isn't recognized just yet.
Can you get sued? Sure. But putting a disclaimer in any license doesn't change the fact anyone may sue you at anytime for any reason. BUT IF YOU WANT YOUR UNCONDITIONAL LICENSE TO SCREAM A LITTLE 0BSD WILL GIVE YOU JUST THAT. PRACTICALLY SPEAKING.