Yes, BLS Mobil will charge for a day pass or city ticket if this is the cheapest available option.
The calculation automatically optimizes the price of your journeys if this is possible according to the tariff regulations. Some examples from the tariff association Libero:
If you make several trips a day in the same zone and a day ticket would actually be cheaper, you will only be charged for the day ticket. If there are less, only the price of the one-way tickets.
If you make two trips within 90 minutes in the same zone, you normally buy two short distance tickets (2 x 2.00) or two one-way tickets (2 x 2.80). However, it is cheaper if you would buy a 3-zone ticket for 3.60 for both trips together, because this ticket is valid for 90 minutes.
Thanks to the best price function you would not have to think about which would be the right ticket. After each trip, it checks if there is a cheaper ticket combination and adjusts the price of your trips accordingly.