A vegetarian diet has a lot of advantages. It is more environmentally friendly than a diet that relies heavily on meat and fish, given the way that those animals are reared and caught for the plate. It also allows people to get more of their food from their own backyard (as even the smallest of spaces can be used to cultivate some crops).
And it tends to be healthier. This article highlights one of the health benefits: the lowering of blood pressure. Given that disease of the coronary system is one of the biggest killers in modern societies, the advice here for naturally lowering your blood pressure will be useful for everyone, even if you don’t go vegetarian.