AWS Certified Cloud Practitioner

To ensure that users can view videos with low latency, the company should use Amazon CloudFront. CloudFront is a content delivery network (CDN) that speeds up the delivery of both static and dynamic web content including videos, by caching copies of the content closer to the users' geographic locations. This reduces the time it takes for the content to travel from the server to the user, thus minimizing latency.

The ability of a system to recover from infrastructure or service disruptions and dynamically acquire computing resources to meet demand falls under the Reliability pillar of the AWS Well-Architected Framework. This pillar focuses on ensuring a workload is able to perform its intended function correctly and consistently. Topics related to reliability include fault tolerance, recovery planning, and scaling to meet demand, which are directly aligned with the concepts mentioned in the question.

Migrating to the AWS Cloud offers several benefits. Operational resilience is enhanced since AWS provides a highly available and scalable infrastructure, reducing the impact of failures or disruptions. Business agility is also increased as AWS allows for quick and easy deployment of new applications and services, enabling organizations to scale their infrastructure according to demand and innovate faster.

The plan to replace physical on-premises compute servers with AWS serverless compute services in order to take advantage of advanced technologies quickly aligns with the 'Performance Efficiency' pillar of the AWS Well-Architected Framework. This pillar focuses on the efficient use of computing resources to meet requirements and how to maintain efficiency as demand changes and technologies evolve. Serverless computing allows rapid adoption of advanced technologies and efficient scaling, which directly relates to performance efficiency.

AWS Organizations is the suitable service for managing multiple AWS accounts in a large company. It allows centralized management and governance of accounts, enabling policies that facilitate resource sharing, including Reserved Instances, across departments.