Enabling DNT is worth it, but not for the reason which seems obvious. The DNT header was created so Internet advertisers could point and say, "only 0.1% of users have enabled DNT - this is evidence that people don't care about or even WANT to be tracked" in the face of scrutiny by regulators. It's a single extra bit of information about your request; I wouldn't worry about "de-anonymization" resulting from enabling it, but would suggest enabling it as a token gesture anyway.