In these first sections of Progressive Slide Guitar Technique we have been using standard tuning. It is more convenient to get used to slide guitar with standard tuning before trying open tunings.
Traditionally slide guitar is played in open tunings, but standard tuning is becoming more common in modem rock and blues styles.
More recently, slide guitar is being used as an effect in part of a song, or may only be used for a few songs in a guitar player’s repertoire so it avoids the need to change the tuning of the guitar for only one song. You will also be more familiar with the chord shapes and scales in standard tuning that we will be using.