Do I require swiss flexi saver pass for 4 days in Switzerland?

Hi, my journey in Switzerland will be as followed: Day 1 in Zurich Day 2 in Lucerne Day 3 in Bern
I'll then travel to Germany and Austria. On the last day before I fly home, I will be back in Zurich. So in all, I'll spend 4 days in Switzerland. For Zurich, there is the option to purchase the Zurich card at 24CHF. For Lucerne, I'll either be going to Mt Pilatus or Lake Lucerne cruise and spend the remaining half day walking in the city. For Bern, there is the Bernmobile day card at 12CHF. So I was wondering whether there's really any savings or incentives to purchase a Swiss Flexi Saver pass which is 268CHF. Thanks in advance for the advice!