Yet another reason to impliment this functionality:
Many users have been asking (pleading) for the ability to sort (or filter) tasks by time zone, which is also a critical need for our organization.
Unless HubSpot is ready to be implementing a sophisticated process that involves automatically looking up the contact’s time zone based on their address (assuming it was entered), a custom Time Zone property would allow the user to specify them in the contact and then filter tasks on that. Which is obviously just one of many things that filtering on contacts and tasks provides.