Crucial to identifying each instrument, attacks are also altered for expressive purposes by the artist. To the listener's ear, and depending on the exact distance between the microphones, every attack will be either multiple or at least broadened in duration. Coincident mikes don't have this problem for the simple reason that there is no time delay between them. Revealed as this dies away is the sustained body of tone, in which various harmonics swell and decay over time. Within the broadly rhythmic flow of the performance, the artist's precise timing may depend on matching the point of development of the old note to the attack of the new one.
Ribbon mikes seem to do better with the entire piano sound, and with that of other instruments, too.
If I were magically granted three wishes for improving the world's recordings, then as a listener as well as a performer and producer, I would wish for everyone to adopt these practices. The producer who has followed the path I've indicated might well at this point feel sanguine about his recording. He has the performance going well, he's picking it up beautifully with coincident ribbons, and he can finally retreat to his own den, the control room, where the sound heard through the monitor speakers is truly remarkable. At last, he has a high-quality electrical signal to be recorded on tape, cut on a master lacquer, and pressed in vinyl. From here on, it should be a straightforward process.