All true, but I imagine there are circumstances where a criminal doesn’t have time to do all these things.
A criminal always has time to do these things. They are criminals and they plan their crimes. Even in a crime of passion there are ways to eliminate the fingerprints in a short time if you have failed to do so beforehand. This method, along with the stupidity of stamping shell casings, is not going to result in many criminals nabbed for crimes but will put a lot of innocent people who happened to touch the casings or the gun in the past of cleaning is not carried out on the weapon or ammo. Fingerprinting was valuable when it first came out but has lost a lot of its potency by the simple fact of people wearing gloves. There is always a way around everything.