How important are manual controls on CNC machines?

Hi All:

I have a Shoptask lathe/mill that I intend to convert to CNC.
The machine has a fine quill feed that is intended to be
driven by a stepper, but it is junk, with about 0.050 backlash.

I recently bought a surplus anti-backlash ballscrew (preloaded
dual nut) that is long enough for the quill. Last night I
finally sat down and designed the mount for it. The screw
is attached to the quill, and does not rotate. The nut is
attached to the millhead, runs in a double row angular contact
bearing, and is rotated by a timing belt pulley (2:1 reduction
from the stepper).

The original fine feed shaft is parallel to the table. It
has a hand crank as well as the pulley, and could easily be
used manually when the stepper is turned off.

WIth the new design, the ballscrew and the stepper shaft are
both parallel to the quill (vertical). It will be very hard
or impossible to provide a hand crank in the available space.

Am I going to regret not having manual control of the quill?

I do have a scrounged jog wheel, which I intend to hook up to
my CNC system. So when the system is powered up, I can still
move the quill easily. But it will be very difficult to
adjust the quill when the CNC system is turned off.

John Kasunich