If you don’t rigorously verify everything by hand before then, you are telling the world that they must do what you should have done for you. Or more likely, you are telling the world that that you expect free intellectual labor and will be ignored and chastised- and cause more scrutiny to fall upon others who did the work properly.
Except in recent months, I've seen modern agents verify things more rigorously than I do now.
Could be a me thing ofc, but I've found that a human's eyes tend to glaze over while the agent just keeps on checking in more and more detail.
Most importantly, it’s bad at catching things that are not normally part of documented processes or openly reasoned about. I think that this specific weakness is extremely important and exactly how you end up letting something go by that would be trivial to catch for a human reviewer.