Gutenberg at least for 4.9.8 and I presume 5.0 once its folded into WP core but I'm not sure on that, will be opt in. You can, if you're site isn't ready for Gutenberg choose to opt out and carry on using the Classic Editor.

But I guess resistance is futile, this is the direction Wordpress is heading and over time blocks will be the way you handle any aspect of customising you're Wordpress site, room the sub-heading to the background-colour of your Footer.