What is the difference between 2E and 4E?

Could you please elaborate on the distinction between 2E and 4E? As someone with a keen interest in cryptocurrency and finance, I'm curious to understand the specific differences in terms of their functionality, applications, or any other pertinent aspects. Could you provide a concise yet comprehensive comparison, highlighting the key features that set these two apart? Additionally, if there are any notable advantages or disadvantages associated with each, I would greatly appreciate your insights.