I use a password manager to deal with my hundreds of different passwords, and it's pretty convenient to use on my phone and laptop. But the Fido (fast identification online) Alliance thinks getting access to your online accounts could be even more convenient and secure by replacing passwords with your trusted devices. From 9To5Mac:
For example, if you try to login to a website on your iPhone, you would enter only your username and it would then send an authentication request to one of your other registered devices, such as an Apple Watch. You could simply tap to authorize. Similarly, when accessing a service on your Mac, you would be able to approve it on your iPhone – and so on.
Although this might sound like weaker security, it's actually secure. Only one of your own trusted devices can make a request for authentication as you, and only a different one of your own trusted devices can approve that request. An attacker wanting to impersonate you would need physical possession of two of your trusted devices, and to be logged in to both. For example, they would need to have your iPhone and its passcode, and your Mac and its password.
While Apple's system is limited to its own devices, the alliance wants all manufacturers to sign up to this approach, so you'd also be able to authorize a login on an Android smartphone, Android tablet, Chromebook, Windows PC or any other trusted device.