One of the greatest additions to PHP environment is Composer. Together with packagist.org provides enormous amount of packages for every PHP developer. I know, PHP had package manager before it was cool (I'm talking about you PEAR) but Composer was something everyone was waiting for.
Why another static site generator? Because why not. If it's good it should be out there helping others with their static sites. Fun fact about Blade Builder - it was designed as simple tool for frontend developers working with Laravel.