W and who commands showing different numbers of users on Linux system

Hello guyz

I am finding it hard to understand how to get the number of users on my system.
When i run the w command it shows me that there are 4 users on my system and the who command only shows 2 users are logged on the system.
Why do the two commands show different numbers of users as per the output below?

What’s the output of this command?

users

and this command:

who -a

The outputs are below: