In my opinion, content boxes, in the basic setup, have outlived their usefulness with the advent of flexbox. The timeline feature is the only reason I would use this element.

Content boxes (1 per column, no column spacing)

Content boxes (default single instance, 3 columns)

No content boxes, 3 columns, no  column spacing

I prefer this style because you can have different length text and keep the buttons aligned.

Test

Etiam at feugiat nisi. Sed lectus nulla, blandit a auctor a, luctus ac sapien. Maecenas posuere nec nulla vel fermentum.

Test

Maecenas posuere nec nulla vel fermentum. Pellentesque semper gravida ultrices. Nullam.

Test

Etiam at feugiat nisi. Sed lectus nulla, blandit a auctor a, luctus ac sapien. Maecenas posuere nec nulla vel fermentum. Pellentesque semper gravida ultrices. Nullam.