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.