I think we all intuitively know jigsaw puzzles are a great part of our life, but this blog article by Robin Johnston does a great job elucidating just what it is about jigsaw puzzling that is so great.
Personally, I like her point #9 best: that it's a great way to just "be" with kids. So often our interactions with kids are judging or arguing or cajoling, and puzzling together is not about any of that, it's just about spending a brief moment or a few hours working as a team on a big project, and often leads to the most amazing conversations.
Happy Puzzling!