Amplifier is the instrument of the longest standing on stage much longer than the musicians themselves. The amplifier is also a fashion statement because the image of the player. The sound character and his own band of characters can be shown from the amplifier. Instead, the amplifier also serves as a rare thing that people notice, that is, as a stage decoration.
Yngwie J. Malmsteen, guitarist fastest speed metal when we saw on the stage in front of Marshall Speakers up to 10 pieces. It often called "Wall of Marshalls". Yet, maybe three amps can be sounded. We can see Jimi Hendrix on the stage too, it’s about 4-5 Marshall Plexi Amps stood behind him. The Beatles could we see standing on the VOX AC30, even we can see Brian May standing in front of the 9 amps VOX AC30.
The funny thing, many of the players were only carrying case Marshall Speakers without anything. It just for a decoration. Three Marshall Pelxi with crank up full volume made our ears are sick and if done for a long time, it can be dangerous. We can imagine if 9 amps installed full front our ears.
In the other hand, there is indication if a band put the amp on the stage and left it there is a big band or at least it have some crews that can help to carry the amps. So, the prestige of the band will be up and can’t underestimate by the promoter.
Indeed the image is important for a band and the amplifier is an inheritance that can intimidate opponents.