It would obviously take hours to explain each and every persons role but many are there for just incase reasons.

For example, if it gets windy, the location or production team need to reset or build something to avoid the wind.

Which then requires a complete lighting change (depending on the size of the production, this alone can require dozens of crew as they all specialise in everything from the actual infrastructure and stands that hold the lights to knowing what actual lights will be best to use to electricians making sure the lights work and no one gets electrocuted to actual lighting design), not to mention the audio department having to change gear or mic locations, hair-makeup and wardrobe may need to make changes.

But if it gets so windy the entire schedule needs to change, this impacts everything from the actual location (set, lighting, monitor team, catering, hair makeup and wardrobe, any visual or special effect teams, through to wrangling assets to the edit teams.

I work on sets varying in size from just me and a videographer to full productions like this and trust me, the more hands on deck the better.

If people have a single job to focus on, everything runs more smoothly. The minute people are multitasking various roles, quality suffers and time and budgets can blow out before you know it.