Absolutely, Grid is not in competition with bootstrap. It is not a framework, so no having to preload bootstrap and bootstrap.js. Having said that it does dovetail amazing well with bootstrap, so by using both together, you can achieve some amazing page layouts.
If your designs use purely rows and columns then bootstrap is the way to go, but if you need to overlap items, be it rows or columns then you need Grid. I believe Grid will become a major force in web design/development both stand alone and used in conjuction with bootstrap, and possibly google’s materialize, if that takes off. Take a look at Jen Simmons and Rachel Andrew’s work, probaly the two foremost experts on CSS Grid Layout.