The big point is the movement of 1 point (from 9600 to 9601 for example) and the big point value is what is worth this movement in the currency of the market, in this case such a movement on the future Dax is worth 25 euros.
The dax, however, does not move one point at a time, but half a point (from 9600 to 9600.5 and then 9601 to return to our example) and then every tick (of 0.5) will be worth 12.5 (half of 25 euros).
The strategy is applicable on CFDs but you have to be careful with the setup and conditions of the filters if measured on the CFD themselves or on the actual future. Many CFDs do not even follow the precise timetable of the future, the idea would be to run the system on a chart powered by the data of the future and then launch the trade on the CFD.
Obviously the broker must be serious.