so clever, I always used pH paper to test anything but this is simply brilliant.
@Corzhens
Soil acidity is important because some plants need acidic soil (like cranberries or droseras for instance which grow in acidic swamps (bogs ?)) and some like the hydrangea will have different flower colors depending on the soil pH (blue when the soil is acidic and pink when it's basic).
Also you can make your soil more acid by adding peat moss (for special plants) or less acid by adding slaked lime to your soil or in some place where you want to grow something with special needs. pH is better neutral (around 7) so you are in the middle and it will please almost all plants.
It's just an information you use to know it better like if your soil contains clay or sand, ...
It's also important because plants can't absorb all the nutrients they need in the soil when the pH is not adequate for them (especially when too acidic):