You'll find a lot of SIMD code using the multiple calls approach as for far too long C++ compilers did daft things like transfer the SIMD registers back to the stack or refuse to inline when the expression got slightly interesting.
We just moved to Mailgun because SendGrid did something similar to us! Fortunately we only used SMTP so it was a straightforward change, but having a backup for something like Twilio Video would be quite an effort.