Can a temporary email address be used to send mass emails?

Yes.

Most mailboxes on the market can send mass emails. Although temporary mailboxes are temporary, they have the functions of ordinary mailboxes and can also send mass emails. A temporary mailbox is a way for a mailbox to exist.

Postboxes generally refer to the trust-receiving equipment set up by postal agencies at post offices, roadsides or public places to accept mail posted by the public, especially public mailboxes.