That is an unusual way of looking at it.  I see it as the price of admission
to a number of support options after the sale, not just repairs.

1: You get manuals in ENGLISH
2: You receive all factory-packed accessories, such as cables, straps, etc.
3: You receive equipment that complies with all applicable safety
certifications for the US
4: You receive software that is up-to-date and is in ENGLISH
5: You are entitled to firmware upgrades
6: Cameras have menus in ENGLISH
7: You may qualify for rebates that narrow the initial price differential
with the gray market importer
8: You have some degree of assurance that the equipment was properly shipped
to the US, and did not spend time in a tropical warehouse, or was not
salvaged from a fire, flood or other disaster that befell its original
importer.
9: You have access to parts and factory-authorized repairs, presumably by
technicians that specialize in your brand of equipment and who have access
to all factory service manuals and technical bulletins.
10: In-warranty repairs are available, with factory parts and done by
factory-trained techs, not subcontracted to some unknown repair company with
an uncertain track record.
11: The warranty period may be longer than that of the gray market item
12: You get cables that are appropriate for America.  AC adapters are
designed for our 110-volt AC, and power plugs are designed for North
American electrical mains.  You don't have to buy a plug adapter to plug
into our current.

There may be more reasons, but the ones above are good enough for me.  I
personally have no time to play with equipment from questionable sources and
uncertain repair and warranty prospects.  I can think of other ways to
economize.  Everyone must decide the merits of this issue for himself.