Multi-agent vs Single Agent

Hello! Can someone tell me when designing a multi-agent system using CrewAI is better compared to having just a single intelligent agent (like ReAct) with multiple tools? I’m designing a solution for a complex use case that requires pulling data from multiple sources to generate output, but I’m not sure why multiple agents would be better - pretty much everything I can think of that can be delegated to multiple agents, a single agent with multiple tools can also do. Any insights, esp from practical experience would be appreciated.