why this over a cat | sed | sendmail < bcc distro_list?
* All of the power of templates in Go (conditionals, etc)
* Some SMTP providers will complain if there are too many emails in BCC (generally >1000)
* Sends emails concurrently
Side question: says the tool is meant to send "html emails"; can it not also just do string replacement in any composed mail message, like a multiple MIME-part mail message that's composed by some other tool?
Yes, certainly it's a far cry from reliable, deliverable, multi-part HTML/plain, open tracking, click tracking, CANSPAN compliant, transactional email.