My own account is being added to the project, so I can earn the point. And whenever I need something from the private store of the client, I log in with the account I gained from the client or I ask a teammember to download it in the project. There is also the Control Center, but I don't know if adding your own account to the Control Center of the company will give you access to their private Marketplace.
Hi, I always use my own account when working for customers.
It is possible to share private marketplace content with a “group” structure.
You will not be able to upload your items to the company private workplace with your own account, but you can use and download
everything from the marketplace that is added to the group.
Furthermore will apps you create be created under your own company. But it is possible to move these apps to the company of your
customer.
So almost everything is possible with your own account, except for uploading items to the private company appstore.
Hope this helps!