A Hefeweizen is one of the most popular beers in Germany and contains more gas than most beers. The larger surface area of the tall glass breaks down the excess gas resulting in the perfect consumable amount after pouring. That's why you cannot really drink a Hefeweizen from a bottle or can. The thick bottom allows for a strong cheer to stir up and evenly distribute the yeast in a Hefeweizen beer.
In Germany, we say a good Pilsener takes seven minutes to pour. During this time, one pours and pauses iteratively. This builds up a layer of foam on top of the beer, which we call the 'crown'. The narrowing top of the glass allows to build the perfect crown. At the same time, it limits air flow to the beer, as Pilseners tend to go flat faster.
Similar to a Pilsener, a Belgian Blonde is topped with a foam crown. Although Belgian glasses are wider, the Blonde's crown requires a narrowing top. The opening is wider as for the Pilsener, as the Blonde's flavors are intensified by oxigen and therefore, should breathe more. It is generally smaller than a Pilsener, as it contains more alcohol.
Kölsch, or Kolsch in English originates from the beautiful city of Cologne (in German called 'Köln'). A Kölsch needs to be consumed fresh, therefore, it is served in small and very narrow glasses. Topped by the usual foam crown, a Kölsch is usually consumed in two to three large gulps and then replaced by a fresh pour. Because it is exposed to oxygen only for a limited time, the glas does not require a special narrowing shape and is kept plain and bare.