It's in the very first body paragraph of the article:

"A new class of multi-tenant applications has emerged that all share the need to hand each end user their own dedicated execution environment in which to safely run code that the application developer did not write. AI coding assistants, interactive code environments, data analytics platforms, vulnerability scanners, and game servers that run user-supplied scripts all fit this pattern."

AI agents. Chatbot session of 8 hours is a lot. 16 vCPU might be useful when developing heavy application and agent need run application tests. You can think what infrastructure https://claude.ai/code needs.

SaaS offering the usage of LLMs via API. You want to launch something isolated, as quickly as possible, do the minimal amount of work and not have to throwaway all your state.