How can global companies like Apple and Google utilize this Python script to send personalized emails to their clients?

The potential societal effects of using a tool like this Python script could be significant. Firstly, it could enhance privacy and security for individuals and organizations, as it allows for the secure sending of emails with private content and attachments. This could reduce the risk of data breaches and unauthorized access to sensitive information. Secondly, it could increase efficiency and productivity, as it automates the process of sending personalized emails. However, it could also potentially be misused for sending spam or malicious emails, if it falls into the wrong hands. Therefore, it's important to use such tools responsibly and ethically.

Some alternative methods to send thousands of personalized emails could include using email marketing platforms such as MailChimp, SendinBlue, or Constant Contact. These platforms often provide features like email templates, automation, and analytics. Another method could be using a Customer Relationship Management (CRM) system that has email capabilities. Lastly, if you're comfortable with coding, you could use another programming language like JavaScript or Ruby to write a similar script.