For me it's more convenient than curl for three reasons mainly:
1. Easier to organize collections of requests in a visual hierarchy
2. Environments mean you can use the same collection to easily execute against local, dev, staging, production, etc.
3. Pre- and post-execution scripts mean you can programmatically extract values and chain into other requests (think grabbing an access token from an oauth request then using that token for an authenticated request)
It's basically just convenience features, nothing you can't get with other tools.
1. Easier to organize collections of requests in a visual hierarchy
2. Environments mean you can use the same collection to easily execute against local, dev, staging, production, etc.
3. Pre- and post-execution scripts mean you can programmatically extract values and chain into other requests (think grabbing an access token from an oauth request then using that token for an authenticated request)
It's basically just convenience features, nothing you can't get with other tools.