So, the problem is this:
A GM, working science into their fantasy world, but leaning into real science, will run into inconsistencies because the fantasy doesn't match reality.
A GM, working the scientific method into their fantasy world, but not leaning into real-world science is going to have to make up all that "science" information out of whole cloth. How quickly do you figure the GM, spewing pseudoscientific gobbledigook, will create inconsistencies within their fantasy world's system?
And what's the point of it if the "science" isn't going to be self-consistent?