I agree with Mike in the fact that a person playing can pick up the rhythmic nuances of the other instruments, and embellish them or become almost invisible to compliment them. For instance, the piano can be an incredible percussion instrument, then adding an extra defining beat to, for instance a 3/4 time with a cabasa, beaded gourd or tambourine, gives a great acoustic sound, without the necessity of a loop or kit. I personally enjoy playing with a loop or kit because I see my challenge as disguising the "canned" aspect that so many listeners complain about, as well as keeping good time. While nothing compares to playing with a real live drummer who is not rhythmicly challenged, I seem to get rave reviews when I play with a loop, because they think it's me making all the rhythm. I almost feel bad taking all the praise, but have you ever given a machine a compliment? You don't even get a smile or a nod for your kind words.