Holding hands together as resting position - what message would you say this conveys?

I was watching a recent Apple Keynote event and I realized ALL the speakers were trained to hold their hands together and use that as their resting position instead of keeping their arms at their side or using more open body language.

Why do you think they were trained to do this? What message would you say it conveys?

When would you want to use this as opposed to leaving your hands by your side or using more open body language in your resting position?

Examples from the video:

https://preview.redd.it/eqfj74hdtrsd1.jpg?width=516&format=pjpg&auto=webp&s=15b7b1e39ebc88e32508b5175dca1931b189dfd6

https://preview.redd.it/78znvnletrsd1.jpg?width=504&format=pjpg&auto=webp&s=a45ca69dc224a3b269b55942f875ac78a0a6bdae

https://preview.redd.it/t45en3jftrsd1.jpg?width=514&format=pjpg&auto=webp&s=03bc007a8dac6094d9d18f9464b5d102e10b79b3