
Playing the open E string and the B gives a good solid powerful sound. 5th chords are often used in rock and punk music but they still have their place in good old blues.
The E5 chord can also be used to create a simple blues shuffle. Simply combine it with a E6 chord.
Playing 2 strums on each will give you that classic sound heard in some many songs. From Jimmy Reed to Stevie Ray Vaughan they have all used the classic E5 chord.