This article is from the Piano Purchase and Maintenance FAQ, by Isako Hoshino rmmpfaq@yahoo.com with numerous contributions by others.
There is a great misconception among the public that anyone
who uses a "machine" isn't a real tuner. By the same token,
someone who just buys a machine and a few tools don't
necessarily qualify as a "piano tuner." They are both valid
methods. Electronic tuning aid is just that -- an aid to
tuning. It doesn't replace an aural tuning, but is an
assistant -- a tool used by piano technicians to provide the
best service to customers.
Many technicians today use both methods to produce the best
possible tunings. To be a good tuner, aside from being able
to pitch a note, one must understand the overall effect of
the tunings. Technicians who perform electronically assisted
tunings usually do an aural check of the tuning to make
certain that the tuning is the best it can possibly be on
each instrument.
 
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