The adaptive profile updates feature is an advanced setting in an access control policy that applies globally to all intrusion policies invoked by that access control policy. The Firepower recommended rules feature applies to the individual intrusion policy where you configure it.
Like Firepower recommended rules, profile updates compare metadata in a rule to host information to determine whether a rule should apply for a particular host. However, while Firepower recommended rules provide recommendations for enabling or disabling rules using that information, profile updates use the information to apply specific rules to specific traffic.
Firepower recommended rules require your interaction to implement suggested changes to rule states. Profile updates, on the other hand, do not modify intrusion policies. Treatment of rules based on profile updates happens on a packet-by-packet basis.
Additionally, Firepower recommended rules can result in enabling disabled rules. Profile updates, in contrast, only affect the application of rules that are already enabled in intrusion policies. Profile updates never change the rule state.
You can use profile updates and Firepower recommended rules in combination. Profile updates use the rule state for a rule when your intrusion policy is deployed to determine whether to include it as a candidate for applying, and your choices to accept or decline recommendations are reflected in that rule state. You can use both features to ensure that you have enabled or disabled the most appropriate rules for each network you monitor, and then to apply enabled rules most efficiently for specific traffic.