Every client that has had me deploy "Always on" - has had me remove it.  And it's not because it didn't work.
 
I would say the majority of the cases were due to cyber insurance or audit requirements requiring MFA.  Personally, I consider certificates better - but these days, there is often a hard requirement for MFA.
 
Nearly every AnyConnect deployment I have done recently used SAML against things like Cisco Duo or AzureAD.
 
Certificate-based authentication does support "Start before login" using machine certificates.  SAML does not.
 
 
I just checked on one client dashboard - certificate authentication is not a beta feature.  It is a production feature available for everyone to use.
 
