In reply to Bastian.

This isn't bashing PHP in any way. The source, WPGraphQL is built on PHP and empowers the WordPress server in great ways.

This is decoupling concerns though. Letting the WordPress server do server things and letting a new stack of theme rendering do theme rendering things.

It's not a move _away_ from WordPress, but a marriage between WordPress and a new stack.

Partly because, as Kevin said, it's new and shiny, but also because it solves some real problems (speed/security) and improves (arguably) the developer experience.