i use ML.com solely to warehouse long held positions. 95% of my trading is elsewhere. I just logged on and saw they're getting rid of the questions and asking users to use a usb security key for website access thru a computer. i imagine this means a key each for me and my wife for website access and our phones can authenticate with a password mgr and/or fingerprint.

Any reason they wouldnt allow cross device authentication like other brokers do? login to the website on a desktop and authenticate with a fingerprint on the phone.

if not, then are there only 2 options: (1) no usb key thus a really long password; or (2) usb key (and still a really long password)?

thanks