Reply by Loren

The joints move around. Unless you have a fast clamping system that
controls movement of the parts in all directions when you are putting
the screws in, the joints will drift and you have to sand out the deviations.

The screws split wood sometimes, and especially plywoods and particle boards.

They are not a strong joint in melamine and MDF and cause more problems
in these materials than they solve, imo.

The joints look cheap and uncraftsmanlike. Looks DIY.

Still, they have their uses.

I do use pocket holes sometimes, but I’ve discovered their limitations and
regret using them in past work where I could have used something that
didn’t look so awful from the back.