Can you log into 1 operator's ID from multiple devices?

Yes, you can.
ChatPlus can log into 1 operator's ID from multiple devices, so it can be operated in many ways.

Log in from company's PC and Smartphone App

When you are working, you can chat from company's PC and when you are out of the office, you can log in from your Smartphones and chat from there.
When you are eating, or cannot be in the office, it is very useful when you can log in from Smartphone App. (If you install the App, you can get notification when the chat came.)

Create common ID and share chat within team members

Set ID of common operator in [Support window] and log in at the same time from multiple people. If the inquiry came, a member who has free time can reply back to the chat.

If it is the home page under 200 cases of inquiries, you can　handle them enough with 1 ID.
For example,

Normally A would reply back to chat
If there is a question that cannot be answered right away, put an alert
When there is an alert, other person would reply back
Other person would reply back depending on questions

Like this, you can set the operation rule beforehand, to stably operate chat.