Edit: I misread "is" as "could be". It's a good thing to have because it could be a good thing to use. It may be a bad thing to have enabled by default, but it's a bad thing to omit outright.
The potential for abuse is staggering. Yes, it would be good to have to benign purposes, but unless you trust everyone on the internet to act honorably, it's a terrible idea.
Edit: I misread "is" as "could be". It's a good thing to have because it could be a good thing to use. It may be a bad thing to have enabled by default, but it's a bad thing to omit outright.