Even though MTQ contains nitrates I feel this is actually a safer way for most people to make bacon.
The USDA also specifies that cured meats are not allowed to contain more than 200 ppm nitrite.
When most people make their own cure mix from Cure#1 there is tremendous potential for them to formulate incorrectly. Example: Was that 7 teaspoons or tablespoons? Most people will not accurately weigh the individual components on a scale.
Even if they do formulate correctly they may apply at a much higher rate than needed since they do not have a set of manufacturers instructions in front of them.
It is not hard to imagine a scenario where someone formulates their own cure mix and ends up with bacon containing 5000 ppm nitrite. This thread started with a question about a bag of repackaged cure of unknown identity.
If you use MTQ you do not follow USDA guidelines around nitrates. If you use Cure #1 and make your own cure mix you run the risk of not following USDA guidelines around nitrite levels.
In my opinion, the risks are lessened by using the commercial product according to their instructions.