It's always good to have things on hand. If you want shrimp it is good to have for sure. Certain fish like hard or soft water too. Then you know exactly what your water is like.
I don’t know. I’m just curious because I’ve heard that either GH or KH helps keep the PH stable.Do you have a LPS that will do the test for you? In most cases it's not necessary to know the gH and kH but it's nice to know the basic properties of your water. It only has to be done one time and it's a shame to have to buy an expensive test kit to use just once. GH and kH don't change unless your water source changes or the water company add something to the water to prevent metal pipes from corroding.
I’m planning on having platies and guppies. The platy I currently have seems to be perfectly fine with the water (PH of 8.4 straight out of the tap, but around 8.0 I think in the aquarium). Is this 8.0 PH that I’m reading?Aquarium folk need to understand KH. So yes get that tested and learn how it works. The problem you will see on Fishlore is a tank with depleted buffers. That means KH is zero. This can kill an aquarium. So knowing your KH of your source water and tank is good to know for fish keeping.
GH is important for hardwater fish that need high GH. If you want to get into African cichlids you will need to know about GH.