>>> Would it be possible to use it before the strategy is even run? so less processing?
The strategy canvas is designed and meant to be used by a business user. The optimizations you are describing are built in the product, but it is 'invisible' for you. You do not need to worry about it. At runtime, first the condition(s) from the switch rule is evaluated, and only the necessary path is then further computed.
If the Switch component conditions are always evaluated first, what happens if I use a dot (.) operator to refer to strategy / proposition properties in the If condition. The values won't be available until the previous components are run.