AlmostBob wrote:
it will not matter what you request, the other person will not respond with
a read receipt

Nonsense. Most people will respond to a Read Receipt request on
messages which are (manually) confirmed to be from a known good sender.
I do and so do most of my respondents.

As Ron mentioned, one of the choices for the recipient is "Notify me
for each read receipt request", so the recipient can send a Read Receipt
if (s)he is absolutely sure the message is legit, and not send one in
all other cases.

read receipt req are used to confirm email address by spam bots

Possibly, but I have never had such a case. Most spammers use other
mechanisms, like requests to (supposedly) unsubscribe, web bugs, etc..