Rejections are great info, especially quick ones. It's the companies that never respond or start the process then ghost that are the real problem. There you learn absolutely nothing.
You learn nothing regardless. There is never any information about why you get rejected or why you were passed over. The only difference between getting rejected and not getting rejected is that you at least have closure on that application.
I think quick rejections are a good indication to work on your materials and/or position selection, possibly delaying your send rate. Ghosting leaves all the variables hidden on quality vs volume and even leaves it unclear on whether your volume of sends is sufficient (maybe the industry is just slow at coming back and will answer all your past applications.)
