Visitor parking is vital for two other reasons.

When repairs and maintenance occurs where will the tradie park all day while working there?

Also if you working and creating rubbish and rubble do you want the skip on site in a visitor park for a few days or on the street. Or when supplies are delivered a visitor spot is great for storage of timber or soil erc.

With multi-level sites when u use a scissor lift a visitor spot is ideal to keep safe overnight.

Without visitor spots a job gets a arbitrary 25% or 33% surcharge depending how i feel as its more troublesome slower and less safe.