How so? You've got all the same debuggability that you'd have with rest - sure you need to look at your requests and responses through your tools rather than directly, but that was already the case unless you're not using HTTPS (which is a bigger problem). Throw up GraphiQL on one of your developer/admin pages and you've got easier exploratory querying than you could ever get with an old-style Rest API.
How so? You've got all the same debuggability that you'd have with rest - sure you need to look at your requests and responses through your tools rather than directly, but that was already the case unless you're not using HTTPS (which is a bigger problem). Throw up GraphiQL on one of your developer/admin pages and you've got easier exploratory querying than you could ever get with an old-style Rest API.