Bob Phillips wrote...
Are you referring to numbers?
....

No. The result of the concatenation operator, &, is always text.

But the point is that using OR(x&y="foobar",x&y="doodah") when the
fully qualified test is OR(AND(x="foo",y="bar"),AND(x="doo",y="dah"))
can lead to error when, e.g., x = "foob" and y = "ar" or x = "do" and y
= "odah". IOW, x&y=A&B doesn't necessarily give the same result as
AND(x=A,y=B).