Jayson_Virissimo's comments show one reason why it's a poor instrument: it doesn't actually address any of the arguments you actually want it to.

Another reason is that it's a "virtual" argumentum ad baculum. Because it doesn't actually address your opponent's arguments, the only reason it gives them to agree with you is to avoid (virtual) punishment. If it actually does get them to concede the argument, it might be useful, but be aware that it's Dark Arts at best.