Yes, absolutely necessary! 
Many thanks for your posting @SarahX 
The goal of a perfect customer service is to be there for the customer when they need you.
Especially if you want to offer live chat, phone support etc.
Only in this way can the planning of the agents’ working hours be aligned with the customer’s needs. By the day is just not enough!
Doesn’t make sense that the customer service agent is there, but the customers are not… Or the customers are there, but the customer service agents are not.
Therefore: Please 
dear “HubSpot feature prioritization team”:
It would be so wonderful if you could implement the feature. 
Sunny greetings from Martina