It's not clear from the message whether the software is setting up their own email system, if so it will need to be audited and certified, which is a major hassle.
Either way, the auditors and the infrastructure might not want to handle an order of magnitude more traffic (API usage is really in a different league than occasional human email). Expect all emails to have to be stored for around a decade.
Either way, the auditors and the infrastructure might not want to handle an order of magnitude more traffic (API usage is really in a different league than occasional human email). Expect all emails to have to be stored for around a decade.