I probably don't. I know copyleft vs permissive can be heated debates and I don't have a very strong opinion. My decision and reasoning is mostly based/aligned with https://shazow.net/posts/permissive-vs-copyleft/
At the current stage, and as solo dev, I don't believe that either licensing is realistically going to have any meaningful difference. There are plenty of cases where copyleft didn't prevent capture. And permissive projects that thrived above corporate versions.
But I'm curious to learn and appreciate the feedback. Can you elaborate? What's the main concern. What assurances, or protections do you hope to get from GPL? Is it about using the project, or contributing to the project?