Getting the team to the venue is easy. Getting everyone home afterwards, safely, without anyone doing sums about whether they are fine to drive, is the part worth chartering a vehicle for.
A December office party creates a duty of care that quietly lands on whoever organised it. An open bar and a car park is a poor combination, and the modern answer is not to lecture people about rideshare credits. It is to put a chauffeured vehicle on the schedule so that going home safely is the default rather than a decision.
The same shape works for anything with a bar and a car park: a client appreciation evening, a milestone celebration, a team night out after a long quarter.