Explanation
https://www.oracle.com/cloud/what-is-iaas/
What Is IaaS?
Infrastructure as a service (IaaS) is a type of cloud service model in which computing resources are hosted in the cloud. Businesses can use the IaaS model to shift some or all of their use of on-premises or colocated data center infrastructure to the cloud, where it is owned and managed by a cloud provider. These infrastructure elements can include compute, network, and storage hardware as well as other components and software.
In the IaaS model, the cloud provider owns and operates the hardware and software and also owns or leases the data center. When you have an IaaS solution, you rent the resources like compute or storage, provision them when needed, and pay for the resources your organization consumes. For some resources such as compute, you'll pay for the resources you use. For others such as storage, you'll pay for capacity.
How Does IaaS Work?
In a typical IaaS model, a business-which can be of any size-consumes services like compute, storage, and databases from a cloud provider. The cloud provider offers those services by hosting hardware and software in the cloud. The business will no longer need to purchase and manage its own equipment, or space to host the equipment, and the cost will shift to a pay-as-you-go model. When the business needs less, it pays for less.
And when it grows, it can provision additional computing resources and other technologies in minutes.
In contrast, in a traditional on-premises scenario, a business manages and maintains its own data center. The business must invest in servers, storage, software, and other technologies, and hire an IT staff or contractors to purchase, manage, and upgrade all the equipment and licenses. The data center has to be built to meet peak demand, even though sometimes workloads decline and those resources stand idle. Conversely, if the business grows quickly, the IT department might struggle to keep up.

Explanation
Oracle Functions is a fully managed, multi-tenant, highly scalable, on-demand, Functions-as-a-Service platform. It is built on enterprise-grade Oracle Cloud Infrastructure and powered by the Fn Project open source engine. Use Oracle Functions (sometimes abbreviated to just Functions) when you want to focus on writing code to meet business needs.
The serverless and elastic architecture of Oracle Functions means there's no infrastructure administration or software administration for you to perform. You don't provision or maintain compute instances, and operating system software patches and upgrades are applied automatically.

Explanation
Creating a manual cluster of compute instances, and Writing custom scripts that will monitor your solution are not valid ways to ensure fault tolerance at all. Also, Performing Data Integrity check when using OCI File Storage Service is not valid since OCI takes care of it.
Therefore, we are left with:
1) Using multiple OCI Availibility Domains (AD), where available, to deploy your solution - Which is excellent because we have multiple AD's so that if one fails, we have a backup AD!
2) Ensuring your solution components are distributed across OCI Fault Domains - So that we can protect our deployment against unexpected power failures, AD failure etc.

Explanation
When you sign up for Oracle Cloud Infrastructure, Oracle creates a tenancy for you in one region. This is your home region. Your home region is where your IAM resources are defined. When you subscribe to another region, your IAM resources are available in the new region, however, the master definitions reside in your home region and can only be changed there.
When you subscribe your tenancy to a new region, all the policies from your home region are enforced in the new region. If you want to limit access for groups of users to specific regions, you can write policies to grant access to specific regions only.

Explanation
OCI leverages advanced encryption that leads to fast performance, OCI does not over subscribe CPU, but only memory, and OCI hypervisor provides industry leading performance are WRONG.
However, OCI does back claims with SLAs and offers predictable pricing for all services.