Difference between checkout and sales point

[Batarya]

Test No. incompl/advan-16 "At the Shops", question 3

The trouble with these huge superstores is that they don't have enough ......... to deal with customers at busy times.

(a) barriers
(b) sales points
(c) exits
(d) checkouts

Test No. incompl/advan-16 "At the Shops", answer 3

The trouble with these huge superstores is that they don't have enough checkouts to deal with customers at busy times.

Correct answer: (d) checkouts

Your answer was: incorrect
The trouble with these huge superstores is that they don't have enough sales points to deal with customers at busy times.
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why not "sales points"? I couldn't understand and find the meaning of "checkout" here

[Torsten]

A checkout is the place within a store, shop or another commercial establishment where customers pay for the goods they have purchased. A sales point is a place where something is sold.
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