If you want to be a good runner, then you need to run. If you want to be a world record holder in the deadlift, then you must deadlift. If you want to be the best at jackin’ it in your Moms basement, then by golly you need jack it in your Moms basement as often as you can.
There are is a finite amount of abilities that will transfer from one discipline to another. But for those who want to be world-class in their sport of choice at least 80% of their training needs to be doing that specific sport.
Don’t get caught up in the cult of mediocrity.