produces a sequence of octets ENCODED as Latin-1 for code points 0 - 255

It gives the same result, yes, but only by virtue of Unicode code points being rather similar to iso-latin-1, not because print does any encoding.

print does this:

- If any of the elements of the string is larger than 255,
  - Warn "wide character".
  - Encode the string using utf8.

- For each element of the string,
  - Print that number as a byte.
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The operator plus expects numbers, just like print, right?

Two individual numbers, yes. print takes two strings of them. The bitwise operators accept either.

$ perl -E'say "ABC" | "   "'
abc
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