Replying to Summer Ski setup

My plan for the summer was to build my backyard ski setup, however I never had the time to complete it but I'll me finishing it soon hopefully. I'm just wondering how much it really helps your skiing once you're back on the snow, or if people just do it because it's a fun thing to do in the summer. How hard is it to apply your newly learnt tricks to rails? Especially if the rail is a lot different from what you had in your backyard.