Content editors and marketers find it hard to understand a responsive grid system like Bootstrap. With the OOTB SXA features you will have to explain them the grid settings or create fixed layouts with no flexiblity at all. That combination never works.
So we have created a custom implementation of the Bootstrap 4 grid system with two components that deliver predefined column layouts. It is available as a download package on https://barendemmerzaal.com/downloads.html.
This video gives a short overview of how this solution works for both front-end developers and end users.