What is an APRS IGate?

Can you explain what an APRS IGate is in simple terms? I've heard it mentioned in the context of cryptocurrency and blockchain technology, but I'm not entirely sure what it entails. Is it a type of hardware, software, or a specific service? How does it play a role in the world of finance and digital currencies? Is it something that only advanced users would need to understand, or is it relevant for those new to the industry as well?