Odds are very high that it's not for "show"; it's for "dough". Whatever those dummy stacks say on the front, its most likely that company has an agreement with somebody; the artist, management company, promoter. etc., to display the brand on stage. Seems the artist prefers Engl, as he has one running and a backup on standby off stage, front and center in the photo.
This is extremely common, one brand showin' and another brand gowin'. The people paying the endorsement agreement don't care, costs them WAY less than fronting out $10K worth of sell-able real gear to get the snot beat out of, and anybody (who
gives a rats *ss) in the audience left the show and told their player buddies "Dude had
FOUR full -
fill in the blank- stacks man!!!".
Also, not carrying the real deal has a positive effect on the fiscal liability of a tour's cartage and labor costs.
And...
that's ($) the whole point.