Effectively, the other option is passwords, and people are really, really, bad at passwords. Password managers help, but then you just need to compromise the password manager. Strong SSO, backed by hardware, at least makes the attack need to be either physical, or running on a hardware approved by the company. When you mix that with strong execution protections, an EDR, and general policy enforcement and compliance checking, you get protection that beats the pants off 30 different passwords to 30 different sites, or more realistically, 3 passwords to 30 different sites.