As I don't bowl tournaments anymore, since 1996, my interpretation may be a little bit different to most of our current bowlers.
In the "old days" we used to get say 10 minutes without pins, then a few minutes with pins... being an 'old fart' as I am, the first 10 minutes were to simply get warmed up & decide which ball/s suited the condition you were on, then the last few minutes were to line yourself up.
I don't mean to be disrespectful to anyone, but, when I go to a tournament, and that isn't very often, I see a lot of the today's bowlers go straight down to bowl & don't appreciate the importance of warming up. They simply hope they are switched on physically.
Practice without pins can 'warm you up' BEFORE the tournament starts.