The name picket came from the boards that are used to build this type of fence: these are short, tapered or pointed top, evenly spaced vertical boards, also known as pickets.
The advantage of picket fences is that they provide a sense of privacy without blocking the world from your home. This is considered a classic and practical solution for one's home.
Picket fence is not the best option for you when you need a fence to protect your home from wild animals because picket fence is usually not as high as other fences. It is, as mentioned before, more like an ornament than a barrier. It marks the boundaries but does not create a protecting shield. On the other hand, it makes the visitors feel welcome.
When installing a picket fence, you should bear in mind that picket fence is usually made of wood and needs maintenance. You have to add an extra coat of paint almost every year to keep it look beautiful. Once in five years, you should even scrap the old paint and repaint the whole fence.
Nowadays, there is an option to use plastic that resembles wood for building a picket fence. The usage of different materials will probably gear up to save time.