Fifth chords are also knows as power chords, they are the simplest form of chord to play, also the most popular. The reason for this is that a lot of top 40 and modern songs use them. They are usually played on a distorted amp setting (distortion is a dirty, messy or heavy sound that an amp or effects pedal produces). There are quite a few bands that use 5th chords in most of their songs, a few prominent ones are Blink 182, The Offspring and Green Day and most alternative or punk bands. These chords are popular with heavier bands also because 5th chords sound good while distorted.
A lot of students I have taught go straight for the 5th chords when learning and can usually play a song using them within a week. They are a two finger chord that only has to move up or down the fretboard. If you learn a song by tab that uses these chords you don't even have to know the chord name, just the fret position. A little hint, DON'T DO THIS ! it will turn you into a dumb guitarist. Get to know the chord position names and their root names as well, trust me it makes life easier in the future.