Exchange-Traded Funds (ETFs) have become increasingly popular as a passive investment strategy for equity portfolio management. They provide investors with the ability to gain exposure to a diverse range of underlying assets while benefiting from the flexibility of trading like individual stocks. In this context, discuss the key advantages of using ETFs as part of a passive equity investing strategy.

In your response, be sure to address at least three advantages and provide supporting details for each. Your essay should demonstrate a clear understanding of ETFs and how they fit into the broader scope of passive investment strategies.