It was simply his style. He was the first to do it and he set the fashion for many years.
The picture you are referring to was taken when he was about to leave office. I do not know the reason for it, but it was not a habit. I would guess that is was the photographer's idea. Maybe he thought the pose looked statesmanlike a la Napoleon. In Napoleon's day or before, the hand in jacket pose was a classical pose, rather like having a hand on one's pocket for a relaxed look. The right hand is actually tucked into his vest, not his shirt.
A shirt is an item of clothing that has a collar and may have long or short sleeves. A vest on the other hand, has no sleeves.
It was the fashion of the day for 'gentlemen of breeding' which, of course, Napoleon craved to be. Follow the link It was documented that Napolean had Gout. Usually Gout effects the toes, ankle or knee. It can also effect the hand. When that happens, it is extremely uncomfortable to let your hand rest at your side. It relieves the pressure to hold your hand at your chest. Putting his hand in his coat was an easy way to keep the hand in one position.
A vest is used for both- but not the same vest. A bullet proof vest, and a life vest.
Vest's.
Not a vest, but a cummerbund.
Una camiseta does not mean vest- it is a t-shirt vest is chaleco
Bud Vest's birth name is Roscoe Vest Jr..
Saul Vest's birth name is Vest, Saul Michael.
black vest
A weighted vest adds distributed stress to all muscles. The weight tears muscle fibers so they regrow to be stronger and give an athlete a competitive advantage. Any athlete training for football or basketball could benefit from training with a weighted vest, resting, and retraining without the vest so hand and eye coordination can be re-calibrated. Other occupations like a policeman or sport like wrestling could use a weighted vest to get a leg up on their competition.
For a vest that is already crocheted and available off the rack, your best option is actually a second-hand store. To have a vest custom made, the best option is to visit a local yarn shop and see if any of their regular customers or staffers are willing to take a commission project. And to make your own crocheted vest (the most rewarding option), check crochet patterns check Crochet Pattern Central (link below).