You are correct that as a Part 91 flight you can begin the approach even if
it is reported Zero-Zero, and you are allowed to land if you have the
runway
environment in site when you reach the decision point on the approach.

You must also have the prescribed flight visibility

Nope, just the runway environment.

FAR 91.175 is pretty clear that the prescribed flight visibility is required
to land:

(d) Landing. No pilot operating an aircraft, except a military aircraft of the
United States, may land that aircraft when—
(1) [refers to use of enhanced vision systems]; or

(2) For all other part 91 operations and parts 121, 125, 129, and 135
operations, the flight visibility is less than the visibility prescribed in
the standard instrument approach procedure being used.



Also, as I've already posted, 91.175(c) prohibits even continuing below DH
unless you have the prescribed visibility.