They only did 5 minutes daily for both. I'd argue that

1. breath work has a much smaller minimum effective dosage than meditation. That is to say, 5 minutes of breath work can fulfill the purpose of said breath work much better than 5 mins of meditation can fulfill the purpose of that activity. It takes our brain approximately 11 mins to truly focus on any given activity, so doing a focus meditation for less than 11 mins per day probably isn't going to achieve very much. And

2. Meditation has a much steeper learning curve than breath work and can actually entail a lot of frustration and discomfort in the beginning. It's really not the relaxation or "stress management" exercise it is often marketed as here in the West, but a long-term project with the goal of increasing awareness. But as awareness grows, we are not going to like everything we become aware of. E.g. the first thing many people become aware of when meditating is how busy their mind actually is on a moment-to-moment basis, and how uncomfortable it is for them to sit down and not distract themselves with external stimuli. If you go into a meditation with the express purpose of changing your internal state, as you would with a breath exercise, you've really already lost the plot, because meditation is about acceptance and witnessing of the present moment as it is.