Prague Cool Pass

Basically this is the old Praguecard but rebranded so yes, I have used that in the past when it was only a physical card. Now everything can be downloaded. There are two main Prague City Cards. Cool Pass is one and Prague Visitor Pass is the other. Depending on what you are likely to be visiting then yes, with proper planning and setting a realistic amount of time they will save you money. The decision on which card to buy comes down to the offer on the card. Recently I spent my own time breaking down both cards into what was common between them and what was unique. The results clearly showed that as well as the main tourist stuff like the Castle, the Jewish Museum and a selection of cultural places the Cool Pass aims at people who want discounted activities included but not public transport whilst the Prague Visitor Pass includes public transport and goes for the scenic things like towers. You can read the detail at https://livingprague.com/prague-attractions/city-card-comparison/ (Caveat Lector: livingprague is my website).

You need to have a look at the website and break down what places you intend to visit. I'm going to Prague soon and decided that it wasn't worthwhile, but if you intend to visit a lot of pre-1800 art museums it might well save money.