In Italy, the Arcobaleno Transfrontaliera Day Pass is not a day pass offering travel at will. It is a single and return ticket on the selected direct route. You cannot use it to travel elsewhere than indicated as departure/arrival station, and the journey cannot be done multiple times. The ticket is not valid on any train yet on regional trains (RE and R) only.
In Ticino, however, the Arcobaleno Transfrontaliera Day Pass allows you to travel within the indicated zones at will (as many journeys you want), with any public transport service (train, bus, etc.), and no matter the train category.
All trips have to happen within the time of validity as indicated on the ticket.
Kind regards,
Roland