67mm gives you more coverage than the 42mm board, but it still isn't especially wide. That makes it an easy size to work into many interiors.
Although the face is wider, the section remains 12mm thick. Useful where you want a broader trim without a chunky edge.
The bevel introduces a simple angled detail. Nothing overly decorative — just enough to change the look from ordinary dressed MDF.
If you're painting the finished trim, MDF gives you a surface without timber grain becoming part of the final appearance.
Use it during a fresh fit-out or when old mouldings are coming off as part of a room update.