why for type of activity as activity we get a severe warning to use a DT instead of an activity but for type of activity as Utility we dont get warning
Utility type is meant for Utility activities which are used in Utility shape of flow. Pega assumes it’ll be used for this purpose so the warning is not displayed. But activities are not recommended by Pega so it shows the warning.
Activity - Activities are harder to maintain and not as easy to construct as other rules in Pega. We should not use an activity for calculations or property validations that we can implement as constraint rules or Declare Expression rules.
Utility - Choose Utility for a utility activity, one that automates processing without user interaction.
Activity structure | Pega Academy?