A cloud is marketing speak for somebody else's computer or server. They offer hardware and software resources that can be accessed from anywhere, which may be very useful for your staff and hackers. Many cloud services, including government systems, have been hacked and data copied. Others have been seriously compromised or damaged, leading to loss of service.
We don't trust cloud services, unless the are in-house. What would happen to your business if the email and accounting cloud service you rely on runs into problems and takes two weeks to recover?
When you manage your own cloud, you have control, you decide policies and what services to offer.
Your cloud server can be on your own premises (best for offices)
or on a hosted virtual machine server (best for digital nomad workgroups).