So in your case you are using the Triggers integration, right?
If so, when I look at this specific section about Triggers in the documentation: Adobe Campaign Help | Configuring Campaign-Triggers integration, it states that the transactional message is automatically created when the trigger is published, and that you only have to personalize it (including with profile data).
"If you enrich the event data with Adobe Campaign profile data, you can personalize the message based on this information. To personalize your message, select Transactional event > Event context and select a field."
So to me in any case with a Trigger event you will be able to use the event data, and in addition to that, you can use profile data if you enriched the event.
Event transactional messages targeting an event. The data contained in the event itself is used to define the delivery target.
Profile transactional messages targeting profiles from the Adobe Campaign marketing database. You can use information from the Adobe Campaign database to send a transactional message based on customer marketing profiles.
So basically, if you choose Event, you can only use the data stored in the event itself. And if you se Profiles, you will be able to add more personalization for the specific profile.