Use of Triggeractivities is recommended and avoids a warning condition reported when you save this rule. You can type in the name of an existing activity of another Activity Type, but the activity must conform to these restrictions:
The activity cannot itself commit database transactions, because a triggered activity runs during database commits. - is this to avoid locking, infinite loop and override issues?
Preconditions and transitions in the activity cannot use when condition rules and cannot call functions.
Can anybody help me in understanding the restrictions here.