- It requires us to believe that G-d planted huge amounts of fake evidence.
- It doesn’t actually fit with the text of Breishis anyway.
- It doesn’t answer many of the questions regarding the Mabul, Migdal Bavel etc, or why the order of Creation is wrong.
- It has no real basis in the Mesorah, and in fact the notion of G-d deceiving us in such a way runs counter to normative Judaism (Navi Sheker is different).
- It kills any chance of rationally proving Sinai, since the nesayon theory can trump Sinai too.
- It raises serious philosophical questions regarding rationality and reality, and makes rational reasoning very suspect, if not impossible.
- It says, G-d would never lie to us in the Torah, but totally faked us out with his Creation, yet we know for a fact that only He was responsible for the Creation, yet there are many other plausible explanations for the Torah (e.g. Non Literal). In effect, you are more comfortable saying that G-d is a faker than saying that the fundamentalists are wrong. Weird priorities.
- It will make me ridicule you mercilessly.
In other words, it's worthless.