What is sandbox good for?

Could you elaborate on the benefits of sandbox environments in the realm of cryptocurrency and finance? As a professional practitioner, I'm curious to understand how they contribute to the development and testing of new financial technologies. Do they offer a secure platform to test ideas without risking real capital? Are they used to simulate market conditions and assess the performance of algorithms or strategies? What other benefits do sandboxes bring to the financial sector, specifically in relation to cryptocurrency projects?