They all have their place, it's just that pocket screws are my least favorite. Biscuits are a good way to attach an apron to a flat panel when the panel is ply, particle board, or mdf. They can also reinforce joints of a frame or make it easier to join the two sides of a mitered leg. They may seem amateurish to some but they work well in those circumstances. In some cases they can be replaced with a spline which is even better.
A biscuit, spline, dowel, or floating tenon are all versions of the same idea, namely a pocket in both of two pieces with a piece of wood that fits in both and joins them. A spline and a T & G joint are two of the same thing too. The spline is just a floating tongue that fits in two grooves.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.