An emergency fund is your first risk-control layer

Job loss, health costs, family obligations, or relocation often happen when markets are already uncomfortable. Without a reserve, a temporary life event can destroy a long-term investing plan.

This money exists to be available, not to perform. It belongs in a place with low volatility and easy access. Return is secondary; fast usability is the real requirement.

When reserve money sits in the same account as risk assets, it becomes easy to overestimate what you can afford to risk. Separation creates clarity between defense money and growth money.