I've always wondered what the concept of a "backspace" character was supposed to mean. (I tried printing it to erase a previously printed character, but that doesn't work.)
I guess it's another relic of the idea that computer output goes to a printer rather than a display?
Yes! Terminal vendors had to explicitly support this in terminals, though maybe not just because of printers but because it's actually quite useful.
Note that BS only produces overstrike when followed by certain characters (which we might term "combining" for the fun of it), while most will just change the character at that location. A tty spinner is just |BS/BS-BS\BS|BS... with some delay between each -- no overstrike there.
I guess it's another relic of the idea that computer output goes to a printer rather than a display?