I meant less complexity with the setup and more complexity in just "starting to write a blog". I have used both and I found the experience with Ghost much nicer.

WP will never be faster (and will use more resources) than a JAMStack website.

WP will never be more secure than a JAMStack website. It is literally impossible to deface my static Ghost blog without compromising my upstream provider. This is obviously not the case with any WP site.

WP definitely has its uses. I don't think a personal blog is a good one.