Keeping a text file with passwords in clear text is so much less secure than a proper password manager. Even if the company is breached, at least they are encrypted by a master password and take significant time and effort to brute force. That text file is readable by anyone who gets their hands on it, and with the prevalence of malware, it’s a pretty huge gamble to store passwords on your own computer where you are ultimately the only person responsible for your cyber security.