CSV is simple - just values separated by commas, like a spreadsheet. JSON is more structured, with key-value pairs and nested data. Both have their place.
When to Use What
CSV is great for simple tabular data that needs to open in Excel. JSON is better for complex, hierarchical data from APIs. I convert between them all the time!
These converters are essential for data work. One minute you're staring at a JSON file, next minute you've got clean CSV you can actually work with.