I use Firefox Lockwise and Apple passwords. Whether or not it’s safer is a plus but I just like my passwords being autogenerated and saved, makes life easy. Yes I understand that once they have the password to that account they have all my passwords but the same could be said about an email.
Yes the same could be said about email, but that does not make it a great idea. I don't think putting all your bets on apple/firefox never having a breach or issue is the best idea. As all your passwords are autogenerated and stored, you don't know what they are and can not use them without the manager. I can not in this day and age assume any company or group no matter how good and noble will be around/competent/not evil tomorrow.